- From Whence We Came.
- Carburetor Fuel Starvation.
- Radiator Woes Part 1.
- Radiator Woes Part 2.
- Crank Starting a Cub.
- Running, Stops Won't Start - Rotor? Part 1.
- Running, Stops Won't Start - Rotor? Part 2.
- Battery & Starter Problems Part 1.
- Battery & Starter Problems Part 2.
- Rebuilding Starters and Generators
- White Smoke!
- Smoke, New Rings, No Smoke
- Won't Start - Electrical Phase 1
- Won't Start - Electrical Phase 2
- Won't Start - Electrical Phase 3
- Won't start - Coil? Part 1
- Won't start - Coil? Part 2
- Making a Carburetor Wrench
- Repairing A Stripped Carburetor
- Repairing A Broken Idle Tube
- Fuel Flow Problem
- Carburetor Saved
- Carburetor Leaks & Adjustments
- Carburetor Float Problem
- Is It The Starter?
- Stripped Carburetor to Manifold Bolts
- Governor Rockshaft
- New and Used Parts
From Whence We Came!
Just bought a 1948 cub.
Former owner made 2 four(4)inch long vertical cuts in lower edge of hood, 8" apart from front to back on generator side, with 2 vertical sheet metal fins protruding outward 2", with welded corners, so he could fit a 12V Chevrolet alternator. (Does not look great!)
Would like to cut off the protruding fins so the hood could be bent back & welded back to its original shape & provide cub decals.Because the Cub now has a 12V starter & 12V system, what smaller diameter make/model alternator w/voltage regulator would neatly fit where the generator was formerly positioned?
H. L. Chauvin
Posted By: H. L. Chauvin
Date: Sunday, 25 March 2001, at 11:18 a.m.
If the fuel plug is removed & if fuel the bowl is empty, one realizes that the gas is not gravity flowing to the bowl. Cub's gravity flow is sensitive compared to today's increase pressure with fuel pumps.
No gas flow in a fairly cleaned carburetor & fuel system usually indicates a blockage of fuel caused by:
Clogged fuel screen in carburetor near the fuel line; Closed or partially closed float valve; both of which may be getting clogged with unwanted solid material coming from or through the gas tank. Gas comes from the ground, usually from sand these days, & is not filtered enough when we buy it. Some gas tanks have dirt & the Cub sediment bowl can filter out brick bats, dragon flies, & mice, but it has a hard time filtering tiny minute particles of sand etc., found in some gas & gas tanks.
Dismantle carburetor once more and clean all orifices with inexpensive "spray can" carburetor cleaner which has enough compressed air pressure to usually clean these small openings.
Re-check the very delicate float adjustment & set it to exact specifications -- (with just a couple of 32nds of an inch out of specification dimensions, the float can rest on the bottom of the bowl and not allow the float valve to "fully" open.
Go to J.C. Whitney's website or someone similar and get an in-line, see through fuel filter with replaceable cartridges, rated with at least 40 microns, install as vertically as possible, and clogged carburetors are history.
Go to http://www.jackssmallengines.com/ site or similar site, or small gas engine parts place and get an in-line plastic fuel shut off valve, & leaking carburetors after shutting down engine are history.
When shutting down engine at end of day, close fuel shut off valve and let engine run out of gas, (no gas, no harmful deposits when gas evaporates), and carburetor "gumming/clogging" is history.
Clean carburetors are just as important important as good hearts & lungs,so why not improve the filtering system?
Hope this helps.
H. L. Chauvin
Radiator Woes part 1Hi, This is what I experienced -- from this experience, you decide what is needed -- sometimes these questions are like: How long is a piece of string?, yet some try to help! Engine ran fine for short periods & did not overheat; however had very, very minor radiator leak, almost un-noticeable, but after a few hours, water level became low & over heating began. Always adding a pint or so of water. Tried different brands of commercial radiator flushing chemicals & stop leak about 3 times -- next tried strong mixture of "Tide" mixed with water -- very little crud came out of radiator after draining radiator -- stop leak did not work either. Bit the bullet. First drained the radiator. Second, thoroughly mixed 1 large bottle of "Joy" liquid dishwater soap with water and filled cooling system and allow to remain for 1 week. Also started pouring "Kroil" rust penetration on radiator bolts daily and tapping same to loosen rust. Third, drained cooling system and removed radiator. About 1/4 of radiator bolts sheared off -- Mig welded a washer on each, then Mig welded a nut on each washer and removed sheared bolts -- bought stainless steel radiator bolts to replace these for the next owner 30 years or so from now. In the cast iron radiator base was about 4 cups, (no exaggeration), of black crud -- silt, sand, mud and very thick grease which I removed. Next brought the battered original radiator to an experienced radiator shop who had the bottom plate to work specifically on Cub radiators. They pressure tested it, fixed the leak, and thoroughly cleaned out each tube for $40.00. Then, inserted a water hose into the upper radiator hose wrapped with rags and turned on the water pressure for about 1-1/2 hours -- first Joy liquid suds, crud, and lastly, clear water. Provided new upper radiator hose & reassembled radiator with stainless steel bolts. Refilled with 1/2 anti-freeze mixture. Even though my radiator looks like it survived the Eisenhower's Normandy Invasion on the beaches of France in WW II, no doubt I have one of the happiest Cub original radiator on planet earth. After this experience, I saw where ninety -four million gallons of commercial radiator flush would not have phased this cooling system. Hope this helps,
H. L. Chauvin
Posted By: H. L. Chauvin
Date: Friday, 22 August 2003, at 10:07 a.m.
Radiator Woes Part 2Hi Chuck, This is not to sound parochial or facetious, but the best way to help someone on this Board in my opinion is not to try to "guess" at their problem to try to be the hero solver of the day; but in my opinion to get them to think and diagnose problems for themselves, so one day they will pass on these old time methods to others. The modern component-changing-mechanics of today are lost with setting points and oiling magnetos. Everyone has a computer between his ears that is far greater than the PC's and Macintosh's. As said before, never give people fish--teach them to fish. Now that one is thinking, calmly think what is the problem with the radiator? Is it leaking? Is the engine overheating? If not, maybe you just want to see if your radiator is functioning properly; and/or if you can clean it some without taking everything apart. Think, recognize the problem, diagnose and narrow down and isolate the problem, and then fix it. 1. Leaking? One has to add water fairly often--get it repaired before you shoot the next door neighbor who borrowed it from your wife and burned up the engine while you were at work. 2. Overheating? Remove radiator cap when radiator is full and insert a candy thermometer from ebay, (under $5.00), (or your wife's), that registers from about 100 or 180 degrees to 400 degrees. If coolant too hot, problems--either outside dirty between fins not allowing air to flow; inside dirty not allowing water to flow; some former owner painted the radiator with thick enamel which is insulating the metal fins and not allowing heat to escape; and goodness knows what other causes when kids get to playing tractor farmer. 3. Trying to clean radiator without taking it apart. Sure, why not? Think! Because of no water pump, no impeller to move water rapidly; hence, water flows slower through this radiator and crud tends to settle to the bottom as opposed to being suspended in faster flowing coolant. 4. Drain radiator first of coolant when cold and fill with clear water. Think again! 5. Tie a large white sock to a large funnel and drain radiator into funnel and into white sock. After draining, what's in the sock? Think! 6. Get a coat hanger, bend it 90 degrees and insert it upwards through the radiator drain hole at the bottom and try to scrape the cast iron radiator bottom--turn the coat hanger 360 degrees & use different sizes & shaped coat hangers. 7. Repeat above step 5. Nothing in the sock? Good news! Something in the sock--think what next! 8. If the radiator doesn't leak, doesn't overheat, and the white sock stays clean after 3 or 4 coat hanger twirlings, replace drain plug, fill with coolant mixture and hurry up buy some movie tickets before the next movie starts or what ever. Hope this helps!
H. L. Chauvin
Posted by H. L. Chauvin
Date: Saturday, 23 August 2003, at 12:39 a.m.
Crank Starting a CubHi, Caution: Strongly suggested to insure that all gasoline engines are timed properly prior to cranking to avoid broken arms. All vintage gasoline engines, carburetors, & ignition systems are different, but a well tuned vintage gasoline engine is usually choked once or twice with the throttle set a little above idle, then un-choke it, & crank without the choke to avoid flooding. It may take a few times to learn the exact personality of your particular engine when hot & cold, but if well tuned, it should start easily after you get to know it. At the end of a very forceful 1/4 turn spin, when the flywheel is set in motion, always try to pull the crank out away from the crankshaft pulley. If you are not sure about the timing; or if you are a self-employed doctor, dentist, or professional with no disability insurance & with many expensive bills; or if you are just married; or just cannot afford to break an arm, one (1) fool proof technique for cranking is to carry a 48" piece of emergency rope in your tool box just for cranking. Double the rope in two around the crank handle, stand back clear of the handle, & pull the crank with the doubled rope. The worst that can happen is that the rope will be pulled out of one's hand, but if one has gloves, one will not get a rope friction burn on his or her hands! Hope this helps somebody with a weak battery some day. H. L. Chauvin
Posted By: H. L. ChauvinDate: Monday, 31 May 2004, at 10:41 p.m.
Running, Stops Won't Start - Rotor? Part 1Hi, A simple, "vintage" type Cub diagnosis: Was cutting grass w/1948 Cub yesterday, (magneto & 12V coil arrangement), - engine was smoothly running at full throttle w/no problems - engine suddenly died - tried re-starting - engine spinned & seemed to appear to want to start, but did not fire. First, removed carburetor drain plug - lots of gas flow indicated no fuel blockage to carburetor whatsoever. Second, removed main metering jet, (brass bolt on out-side of carburetor), - blew in jet's side hole while holding finger on opposite side hole to clear jet's tiny hole on center end of jet - no blockage - clean as a whistle - a clogged metering jet could not be the problem either. Third, choked carburetor & tried to "thoroughly" flood the engine w/excessive cranking for about 12-15 seconds, & immediately removed No. 1 spark plug, (nearest radiator) - spark plug wet w/gas; hence, gas is getting to plugs. (Excellent fuel test for proper carburetor operation, intake manifold leaks, & fuel flow in gas lines). Fourth, laid No. 1 spark plug on its side, & cranked engine w/hand crank to observe firing - plenty of spark. (Excellent test for function of contact points, condensor, coil, ignition switch, & electrical wiring). Fifth, cranked engine again about a dozen times w/hand crank - plug correctly fired consistently w/no intermittent fire. (Excellent test for clean wiring connections & non-grounding of hot wires). Sixth, tried stop cranking immediately before the extracted No. 1 plug fired - removed distributor cap to observe that the rotor's metal perimeter contactor was correctly pointing approximately towards the 10 o'clock position which means it is about to correctly distribute the coil's fire to the No. 1 spark plug lug in the distributor cap - rotor also observed not to be binding on adjacent rotor cap. Seventh, engine's no. 1 combustion chamber definitely has both gas & fire - what now? Only the obvious - it was running fine just a minute ago, now it does not even fire the No. 1 cylinder - just sit down, relax, & THINK! Eighth, went back to the engine crank, turned engine slowly & again stopped immediately prior to the fire reaching No. 1 spark plug - removed distributor cap, & again, rotor was in correct position; however, came back to the carburetor side to observe the engine timing pointer & the "Vee" in the crankshaft pulley -the steel pointed pointer was not pointing to the "Vee" in the crank shaft pulley. Ninth, removed the rotor cover cap, removed the well greased rotor, & removed the well greased metal rotor pinion gear. Problem Found: The metal rotor gear teeth were worn so thin that 2 of the metal teeth bent down flat & allowed the rotor to rotate out of timing with the engine valves & pistons; hence, even though the engine fired, the engine did not fire at the right time when the carburetor's fuel mixture was compressed in the combustion chambers. Plastic rotor gears were observed to be worn down to about 50%. Solution: Called C & G to order $30.50 rotor, part no. 351 692 R91; & $12.75 rotor pinion, part no. 251 526 R1. With a little luck, & no tornadoes, it should be running in about 15 minutes after parts arrive. Hope this helps somebody one day! H. L. Chauvin
Posted By: H. L. Chauvin
Date: Monday, 23 May 2005, at 11:52 a.m.
Running, Stops Won't Start - Rotor? Part 2Hi, Rotor re-installation: In reference to message below, "Running-Stops-Won't Start - H. L. Chauvin- Monday, 23 May 2005, at 11:52 a.m.", the new rotor gear & new rotor arrived today. Christmas in May. The rotor gear is high grade plastic as opposed to the original metal, & because both the new rotor & the new gear were manufactured by the same manufacturer, (CSH, international parts manufacturer for Case/IH), the two (2) gears are a matched pair with the same individual gear pitch which mesh perfectly w/no loose play; hence these will give years of service because of less gear friction. Often points and plugs are checked in magnetoes, (originals & battery operated w/coils, either 6V or 12V), & some guys have difficulty reinstalling the rotor correctly. Some reinstall the rotor 180 degrees off etc. etc. as can be seen in many messages, however; First, find the raised horizontal mark on the top of the tooth of the small rotor gear & paint it white w/typewriter White-Out-Paint. Second, find the raised vertical mark on the side of the rotor, (opposite side from the rotor metal contactor which distributes fire to the distributor cap plug lugs), & paint a white mark above the gear slot, (i.e., between two (2) rotor gear teeth). (The white marked rotor gear tooth has to be positioned to mesh in the white marked gear slot of the rotor to properly provide exact timing of the engine). Third, clean all gears, adjacent magneto plates & metal rotor stud, & apply a small amount of distributor cam grease, (small tubes from auto parts places), on the top & bottom rotor surfaces, underside of rotor cover plate, round metal rotor stud on the magneto plate, rotor teeth, & rotor gear teeth. Fourth, place the rotor gear on the magneto shaft lightly & turn it until it securely slips into the recess. This gear will only fit one (1) way & can be properly installed only in one(1) way after it slips in its slot. No way can one make a mistake with the position of this gear if its in the slot. Fifth, turn the engine with a hand crank until the white mark on the rotor gear is pointing upwards exactly towards 12 0'clock. Sixth, place the rotor on the rotor stud with the white mark pointing downwards exactly towards 6 o'clock, (i.e., the two(2) white marks should be aligned whereby the gear on the rotor gear is fitting in the gear slot of the rotor. (The white marks are really "Holy Marks" because both raised marks on the black rotor gear and the black rotor are "extremely" difficult to see if you are over 45, if your shop does not have adequate light, or if you are doing this at night in the field with a flash light, or this is done in the hot glaring sun with cold beer -- the "Holy Marks" reduces foul language & high blood pressure when the two (2) marks are not aligned & it does not start! Seventh, only after verifying the proper positioning of these gears, install the rotor cover plate. (When the engie is running, the rotor gear is turned by the magneto shaft which rotates with the engine. The rotor sits on a stationary metal stud & is turned by the gears of the rotating rotor gear). Eighth, install the distributor cap, hug your wife or girl friend, & crank it up. It will run -- mine did - without foul language - just this time anyway! Sincerely hopes this helps someone some day. Humbly submitted,
H. L. Chauvin
Posted By: H. L. Chauvin
Date: Thursday, 26 May 2005, at 12:09 a.m.
Battery & Starter Problems Part 1Hi, Hope this helps someone someday. Problem: Went to start Cub yesterday morning, pulled starter rod, but starter would not turn. No noise, no buzzing, no nothing; however, last weekend it had worked fine with this same "old" 12 volt negative grounded battery. (Last year the battery (-) ground cable turned green in the bolted battery connector & had too be replaced after it failed to ground the battery.) Charged Battery: Hooked up battery charger & let charge all day & night. After trying again this morning, again starter would not turn. First Cub Battery Voltage Test: Removed battery charger cables & set digital multimeter probes on positive (+) & negative (-) battery terminals, (red on red, black on black) & the multimeter registered about 14 volts. First Cub Battery Cable Test: Removed (+) red battery cable at starter, touched with red probe -- repeated multimeter voltage test to an engine negative (-) ground -- same 14 volts reading. Checked Different Battery: Went to my car battery to check multimeter reading on a "good" car battery -- approximately same 14 volts. Cub Battery Cable Ohms Test: Set digital multimeter to ohms readings & touched multimeter red probe to black probe & got reading of 5 -- next placed multimeter probes on both ends of both Cub battery cables, one battery cable at a time -- reading of 5. No doubt both Cub battery cables & all four (4) battery cable connectors are OK. Electrical Double Check: Got out jumper cables; connected black from a ground to (-) Cub battery terminal & red from (+) battery terminal to Cub starter lug & pulled starter rod -- nothing. Second Cub Battery Voltage Test: Performed voltage test on both ends of both (+) & (-) jumper cables -- same 14 volts multimeter reading. Test Starter & Starter Switch on a Different Battery: Removed starter, went outside to car, connected (-) black jumper cable to car battery (-) post & to starter rear cast iron round bendix housing. Connected (+) red jumper cable to car (+) battery post & to starter switch lug bolt. Held starter firmly after placing starter on a plank & pulled starter switch -- starter turned like a WW-I 16 cylinder radial airplane engine. This meant starter switch OK & starter OK. Removed old battery, installed a new 12 volt battery, & everything works fine. Moral of Story: For those of us who remember the old time batteries that died ever so slowly, (re-charging them & extending their lives for months), we of that era have to be reminded that many of today's batteries no longer die slowly -- its like they have a massive heart attack or stroke because they have high cholesterol today, & in a split second, they are gone, even though they register 14 volts or so with a multimeter. Final Battery Test: Could have save a little time by first testing the liquid in the cells of the "old" Cub battery with a battery testing hydrometer, but had to get fancy with a new modern digital multimeter. The battery testing hydrometer measured fine for five (5) cells, but the last cell adjacent to the(+) battery terminal was stone dead & did not accept a charge. Most sincerely, H. L. Chauvin
Posted By: H. L. Chauvin
Date: Saturday, 22 May 2004, at 9:07 p.m.
Battery & Starter Problems Part 2First: In all sincerity, maybe try this -- Think -- What is the only source of electrical energy on your Cub when the engine is not running? Sure, you got it, its the battery. Second: With a $0.97 cent Wal-Mart hydrometer, (w/the 4 little spheres floating), or a $4.99 Multi-Tester from Harbor Freight, one can ascertain that the battery is OK & it appears you may have done that; but if not, check it & assume nothing. (Even fresh new batteries right off of the shelf are faulty & can give any mechanic fits). Third: Just remember that electrical current runs through electrical conductors, (wires & connections), just like water runs through pipes, i.e., + to -, or - to + depending on how your battery is grounded. Fourth: If your + side of the battery is connected to the un-insulated body of the tractor, & if the - side of the battery is connected to the insulated starter switch, the minute you engage the starter switch, current goes through the starter only if the starter is properly grounded, thus completing the circuit. (If there is a loose connection, a corroded connection, or a broken conductor, (wire, etc), the circuit is broken, it's just like cutting a water hose in half whereby water will not reach the nozzle -- wife's flowers will never get watered. Fifth: This may seem extremely parochial, but if you start at the + & - post of the battery with even a test lamp or similar electrical testing device, & proceed through every connection, you "will" find the broken water hose -- no doubt, with a lot less effort. (If one gets "Senior Moments" where you forgot what you checked after the phone rang, maybe draw a little electrical diagram to remember what was already checked so you don't have to start over after the call was the wrong number anyway). Sixth: Please come back to report what you found. Last summer my Cub stopped all of a sudden. I pulled the starter & "nothing". What now? Reached in my tool box, got a multimeter -- battery & battery to battery connections were fine; however, the copper wire going to the starter was green at the clamped connection where it entered the soft metal battery connection -- cleaned it, ran fine but bought a new battery cable the next day. It may be said that "it's a good idea to try to solve electrical problems from the source to the problem & not from the problem to the source". And we all learn new things each day if we listen. Draw an electrical navigation map & go in one direction -- Columbus did something similar in medieval times quite admirably & he didn't even have a flash light. Sure hope this helps, H. L. Chauvin
Posted By: H. L. Chauvin
Date: Friday, 27 May 2005, at 5:15 p.m.
Rebuilding Starters and GeneratorsWith vintage starters & generators, usually the softer metal bushings and softer metal brushes wear first, thus causing starters to "drag", & generators to stop charging. This is many times normal wear & can be expected after a few years. If the armature is good, many starters & generators can be rebuilt in one's garage with simple tools. Rebuild shops have more elaborate "growler" testing equipment, lathes, etc.; but this equipment gets expensive. Some of the very early cars had a one unit starter/generator, whereby the single armature would be turned by the starter commutator & starter brushes on one end, & after the engine started, the separate generator brushes & separate generator commutator on the other end would generate electricity -- a good generator will run like an electric motor if connected to a battery. Principles & methods for rebuilding starters & generators are very similar, so even though we'll address the starter, this rebuilding procedure will in general apply to both starters & generators. First disconnect the battery, disconnect the battery cable at the starter & starter switch rod, & remove the starter. Take an ice pick or a scratch awl & mark the cylindrical starter case & the front & rear covers before disassembly so it can be assembled like it came apart. Remove the 2 long starter bolts and gently slide the front cover off a little & look inside to see how the brushes rest on the commutator, & how it is wired, & then remove the covers & remove the armature observing everything. Prior to removing bushings, check to see if they are available at IH or your local automotive store or hardware store. On vintage starters, bushings can wear enough for the armature to come too close to the coils on the side of the starter causing malfunctioning. This can be normal long time wear. Replace front and rear bushings. Next, the stationary brushes wear, become shorter & need to be replaced to have good contact with the smaller diameter non-ferrous commutator on the steel armature. Remove old brushes and install new ones. If new brushes are not available, similar brushes can sometimes be carefully cut with a hacksaw & be cut to fit. Next, when the brushes wear, particles of brush metal gets into the grooves in between the commutator segments & allow electricity to be conducted between the individual insulated segments of the commutator, thus grounding out the entire armature. This is normal wear & needs maintenance just like other moving parts. Usually if the commutator is badly worn, one can see where the brushes were wearing the commutator. If badly worn, new brushes will not rest solidly on the deformed commutator. In a starter repair shop, the deformed commutator is turned and made smooth on a lathe to true up the commutator so brushes will seat properly. No Lathe, No Problem: If one does not have a lathe, one can Cut 2 1x6's equal length, about 6" long, & cut 2 equal "vee's" centered in top's of both 1x6's, about 7/8" deep and 7/8" wide, (clamp 1x6's together & cut simultaneously). Secure both 1x6's vertically to the ends of a horizontal 2x6 so starter shaft can rest horizontally in & on top of both "vee's" cut in both vertical 1x6's. Screw a horizontal 1x4, (on edge), to both sides of the vertical 1x6's such that the top of the horizontal 1x4's are about 1/16" lower than the top of the horizontal armature. Make sure the starter shaft is level in "vee's" & 1x4's are level & in the same level plane as the armature & commutator. With uniformly cut thin wood shims, place wood shims on both 1x4's such that the tops of the shims are level with the highest part of the commutator. Place a good clean, flat wide file on top of the shims & turn the armature with one's hand & after removing a shim or two, gently allow the file to remove metal from the commutator. The commutator is soft metal and will be removed easily. If bushings were worn, the commutator may not be concentric, but will become concentric in this jig -- important to bear down on armature when turning to keep starter shaft true. After commutator is cut true with the wide file, remove armature, and gently polish commutator with fine water sandpaper -- have your wife hold the armature on the end of work bench & shine the commutator like one would shine shoes with a shoeshine rag -- but, do it on all sides. At this time the insulating mica in between the segments of the worn commutator is almost flush with the surface of the commutator. If left as is, starter brush metal particles will span over the mica & ground out the armature. Next take a good, fine tooth hacksaw blade & remove most of the "road" out of the blade by running the sides of the hacksaw blade on an emery wheel. Wrap part of the hacksaw blade with electrical or duct tape to form a handle on one end. Set the armature in the wood jig, have someone hold it firmly, & very carefully saw the mica out of & between the segments of the commutator to a depth of about 0.018" to 0.020". Again get the fine sand paper & gently shine the rough edges of the hacksaw marks so the brushes don't wear on a rough commutator. H.L. Chauvin
White Smoke!Hi, Jim's correct in assuming that white smoke is most probably caused by water. Next, where is the water coming from: Not knowing your details, if not some kid pouring water in the muffler then? Maybe try removing all 4 spark plugs -- if one or more plugs are very clean, they have been steam cleaned by water leaking in the combustion chamber(s). Try checking the torque on your head bolts and tighten very carefully if loose. If this head gasket tightening does not stop the white smoke, it could be a blown or leaking head gasket, whereby head removal is necessary. A cracked head or cracked engine block would be worse; but if left unattended, leaking water could cause the piston rings & cylinders to rust whereby the engine would freeze. Hope this helps. H. L. Chauvin
Posted By: H. L. Chauvin
Date: Monday, 11 August 2003, at 8:04 p.m.
Smoke, New Rings, No SmokeHi, This may be as hard to believe as it was to believe the earth is not flat. Maybe it may be best to stop here and not read this, but this is how it was done years ago when people could not afford total engine rebuilds & did not listen to engine manufacturer recommendations & dealer mechanics. Can removing old rings & providing new rings without reboring cylinders stop engines from smoking? Yes, in some cases, & Why? Well: When I removed my radiator for repairs, I removed the head and pistons because the engine was smoking & plugs were fouling. This 1948 cub still had worn standard bores with no added sleeves, & the original worn pistons were not oversized. New standard, non-oversized Case/IH pistons & rings are used when the block is bored to 0.010" oversize; i.e, there are no 0.010" oversized pistons & rings, so the standard rings do what they were desiged to do, i.e. expand to the 0.010" oversized diameter. (This is why one needs a strong ring compressor to install rings). Don't know how many times rings were changed in this Cub prior to this, but cylinders had worn to 0.005" larger in diameter at bottoms, & had worn to 0.015" larger diameter at tops. Someone previously had removed the metal ridge at the tops of the cylinders with a ridge cutter, so the cylinder ridges noticed were only carbon ridges which were completely removed with carburetor cleaner on a regular Kitchen scouring pad. Original cast pistons were worn 0.001" at bottoms of pistons & worn to 0.012" smaller diameter at tops. Could not find markings on old rings to determine former ring manufacturer. New standard Cub bores measure up to 2.6234" diameter & new standard Cub pistons measure down to 2.625" diameter; hence, up to 0.004" clearance in diameter, & 0.002" clearance on each side of new pistons -- normal in new engines. With piston & cylinder wear in this 1948 Cub vs. a new Cub, there was approximately 0.015" + 0.012" - 0.004" = 0.023" too much wear & clearance between the piston & cylinder diameters, & 0.0115" too much wear & clearance on each side of the piston. With this much wear & clearance, engine manufacturers would recommend reboring, & buying new oversized pistons; but remember who wrote their books & who sells the pistons & other parts. Bought Case/IH standard rings, (the top ring was chrome), made one pass with oiled honing stones turned slowly on a hand drill so as not to remove valuable cylinder material. Put it all back together, ran it for about 2 hours. It quit smoking after 1 hour. Cut 2 acres of heavy grass with no smoke. Did not take compression tests but in starting with hand crank, one could feel the increased compression. Old valves in old valve stems were quite worn & left as is. Because the Cub valve chamber is on the side, (old "L" head), & not overhead, it is more difficult for oil to be drawn upward to burn in the combustion chamber as it is for oil to flow downward to burn in the combustion chamber as is the case with overhead valve chambers in today's engines. Years ago when poor people had smoking engines, they would remove the rings, clean them and re-install them. With non-detergent oil, when pistons would move downward the rings would stick to the pistons & not expand to the worn larger upper diameter of the cylinder. Today with detergent oil changed regularly, rings stay cleaner and compress and expand better in cylinders. Sincerely,
H. L. Chauvin
PS: Forgot to mention in the 11th paragraph that the hand held drill was not a high rpm electric hand drill, but a 1930's non-electric hand crank drill turned slowly to insure not scoring cylinder too much & not removing this precious cylinder metal. For a Cub, with it's outstanding 1940's engineer designed features, I would imagine & hazard a guess that if one initially would clean out the oil pan, oil strainer, & oil filter container, change detergent oil & filter often, & maintain a proper radiator, one could wear out 10 upholstered tractor seats & the seats of 75 blue jean pants before having to change engine rings twice. Sincerely,
H. L. Chauvin
Posted By: H. L. Chauvin
Date: Monday, 17 May 2004, at 3:38 a.m.
Won't Start - An IntroductionUsually in a "won't start" situation, a master mechanic would choke the engine & try to almost flood it, & next remove a few spark plugs. If plugs are wet with gas, usually a sign of engine getting fuel & is usually not a fuel problem. Next, remove plugs and crank engine. If no fire at plugs, (when they are grounded such as laying on their sides in contact with the top of the engine), it is usually an electrical problem. Verify setting gap on plugs @ .023". Clean plugs if fouled. Make sure you have metal plug wires & metal coil wire -- carbon core plug and coil wires will get ruined with a magneto & eventually won't conduct electricity. Get Q-tips and gasoline to clean distributor cap inside & out, & in all spark plug and coil holes. Replace plug wires in proper order, i.e., wire at 12 o'clock in the distributor cap, (No. 1), leads to the No. 1 spark plug next to the radiator -- (look for the "1" on the distributor cap); 3 o'clock wire in dist. cap leads to 3rd, No. 3 plug from radiator; 6 o'clock wire in cap to 4th, (farthest) No. 4 plug, from radiator; & 9 o'clock wire to 2nd, No. 2 plug from radiator. Remove wires from coil, clean connections, and re-install wires. Thousands of people throw away good coils each year when all they had to do was to clean these electrical connections. New coils mean clean connections -- coils last 40 years & even more. If still no fire, or non-regular, intermittent fire in plugs, report back. Usually points are dirty, not set with proper gap, or the connection for the condenser wire and blue steel spring for points connection is corroded and not making contact. This connection in the magneto is the most important. Thousands of people would change points & condensers thinking the points and condensers went bad -- if they only knew that if they would have cleaned this connection, the points & condensers could have been re-installed, cleaned and used for another 30 years. H.L. Chauvin
Won't Start - Electrical Phase 1Hope this may help someone in a cub "won't start" electrical scenario. If the battery is dead, get a new battery. Make sure plug wires are in proper firing order or engine will backfire, sputter, and will never run properly. Excuse being so parochial & excuse the length, but if one inspects the points and does not time the rotor & engine correctly, the cub will never start. If one chokes the engine, removes spark plugs & they are wet w/gasoline, usually one has an electrical problem & the engine is lacking fire or lacking fire at the proper time. Engine needs both "proper fuel" & "timed fire" to start. Phase 1 Remove plugs, lay on engine head for a good ground, and if no fire, or intermittent fire, one usually has electrical problems. Whether one has a magneto, magneto & coil, or distributor & coil, first disconnect battery & try removing all electrical wire connections, one at a time, at the switch, amp meter, coil, coil transistor, & all connections, etc., clean, & grease connections with regular wheel grease or better yet, marine grease, & reconnect these wires, one at a time. (Grease keeps moisture off of wire connections, battery connections, etc.; w/no moisture, no corrosion; hence, no oxidation & no metal oxide to prevent conducting electrical current in humid climates. Next clean & gap plugs. Insure no carbon core wires -- use only metal core plug wires and coil wire -- magnetos eat up carbon core wires -- so do distributors after some time! Remove & clean distributor/magneto cap with cleanser such as rubbing alcohol or paint thinner, or a very small amount of your 100 proof whiskey -- keep some whiskey for later. Connect battery & try plug fire again -- if no fire at plugs or intermittent fire, have patience & proceed to Phase 2. Posted by: H.L. Chauvin
Date: August 18, 2001
Won't Start - Electrical Phase 2(This article will cover magnetos w/coils) Phase 2 Again disconnect battery. Remove distributor cap. Remove plastic cap at rotor. Remove rotor & small metal gear from magneto. Remove wire connected to side of magneto & to avoid losing your cool & religion or both, loosen bolts & remove the magneto in lieu of trying to correct this with the magneto installed. Remove points, wire from condenser, etc. Clean both faces of points, if pitted, on a knife sharpening oil stone -- if lightly pitted, shine with a piece of double folded fine water sandpaper, on a Popsicle stick, similar to your girl friend's fingernail emery board. Clean insulated stud inside of magneto and all connections. Provide a small amount of grease on the bushing on the points, and install a small amount of grease on the lobes of the magneto cam. Adjust points to 0.020" when arm is on high point of lobe, e.g., points should close tightly and open no more than 0.020" when magneto is rotated. Go to the carburetor side of the engine and apply a small amount of white paint to the very tip of the "timing" metal pointer pointing to the flywheel pulley. Rotate engine with crank and apply a small amount of white paint to the "vee" notch in the flywheel pulley -- if flywheel pulley has two (2) notches, apply paint to 2nd notch only. Wipe pulley with finger so white paint is only in bottom of "vee". Remove all 4 spark plugs, rotate engine with crank "clockwise", while holding finger over no. 1 cylinder spark plug hole, (spark plug nearest radiator), until one feels air pressure on one's finger from the piston rising to top dead center, TDC, on the compression stroke -- stop & again slowing turn engine "clockwise", (when facing rear of tractor), & carefully align painted metal pointer with painted "vee" notch in crankshaft pulley. When metal pointer is aligned w/"vee" notch in crankshaft pulley, cylinder no. 1 is at TDC. This is most important to time the rotor: Insert the small metal gear on the magneto shaft -- this metal gear will only fit one way on the flat part of the magneto shaft. There is an embossed mark on this metal gear which should be temporarily positioned at 12 o'clock. Apply grease to this metal gear and to the plastic rotor gears. Point the protruding metal part of the rotor, (part that almost makes contact with the metal parts inside the distributor cap), to 12 o'clock also, such that the plastic casting mark on the rotor, (between the gears), is at 6 o'clock and aligned with the metal gear below, which is pointing to 12 o'clock. (The single embossed marked metal gear tooth at 12 o'clock should fit between the two (2) 6 o'clock plastic gear teeth of the rotor). Replace rotor cap and make sure rotor turns freely without binding. Now, with no. 1 piston at TDC, (painted metal timing pointer on painted "vee" crankshaft pulley mark), the rotor should point to about 10 o'clock when the magneto is re-installed -- if it points to about 5 o'clock, it is 180 degrees off and one can wear out 1,000 starters and 500 hand cranks and the cub will never start. Lightly tighten magneto bolts so one can still rotate the magneto for timing. After cleaned internal connections for wires in the magneto are assembled, points are clean, and magneto is in place, re-connect battery. Connect coil/magneto wire to coil or magneto & allow other end of coil/magneto wire to come within 3/4" of an engine ground. With a plastic or wood handle screwdriver, open and close the points. Each time the points open, there will be a very slight spark at the points, but the spark from the end of the magneto/coil wire to ground should jump 3/4" easily with a strong spark accompanied by a good "clicking" sound. (Don't hold or touch this coil wire or points when opening points unless you want to get the shock of your life). If no jumping of fire of 3/4" or even more occurs -- possibly a dead battery, dirty points, or bad electrical connections. Contrary to parts supplier opinions & other salesmen's opinions, the condensers, coils, & magnetos hardly ever get weak -- when they go, they go out like a light bulb all at once; & very, very seldom. If good fire off of coil/magneto wire, rotate magneto towards engine block until it touches the engine block. Rotate engine again with crank until white marks align at TDC on compression stroke, (w/pressure on finger), then rotate magneto away from engine until click is heard & mark magneto & engine with pencil at this point & slightly tighten magneto. Rotate engine again until white marks align on compression stroke, (w/pressure on finger), & magneto should click when white marks align -- if not, adjust magneto and repeat until magneto clicks when white marks align at TDC of compression stroke. Cub should purr like a kitten. If no clicking magneto sound when magneto is rotated at TDC, idler gear and governor gear is not synchronized, and need synchronization using white paint on marked gears. Posted by: H.L. Chauvin
Date: August 18, 2001
Won't Start - Electrical Phase 3A few board members kindly requested Phase 3 by e-mail, so I'll try composing this today, just in case its urgent. This is for timing a governor/magneto set up with or without a separate attached automobile or tractor coil. If your magneto doesn't click when you rotate it away from the engine, (as mentioned in the above August 18, 2001 Phase 2), the governor is not timed with the engine idler gear, & even though it may run, the cub will run better when timed properly. Most important, is that with a properly timed magneto & timed engine, this means a much better chance of no broken arms when a cub is started manually with a crank. This may concern some to try this governor/magneto setting, but it can be done with patience & a bit of a positive attitude! Phase 3 Disconnect the battery. Remove the magneto/distributor cap & remove the magneto. After removing the magneto, on the front governor side of the magneto, remove the center bolt & remove this steel spring cover to clean & oil the interior parts & the internal magneto coil spring. Usually this area is rusty, so clean the insides & spring with steel wool, oil well, & re-assemble to insure better magneto clicking operation. Good tools to have for Phase 3, (if you want to avoid losing patience & self confidence), is an inexpensive mechanic's adjustable mirror, (about 2" diameter), on about a 12" long metal swivel stick handle, a flashlight, & any kind of white paint or better yet, a quick drying secretary's white correction typing fluid. (Small "make-up mirror" can also work -- don't use one from your wife -- it will be too difficult to clean afterwards). Next, pick up a regular newspaper and look for a period at the end of a sentence. This is a very "small" dot, but this is what you'll be looking for on the rear, flat side of the perimeter of the governor gear, & the rear, flat side of the perimeter of idler gear, (e.g., the magneto side of both gears). Go to the carburetor side of the tractor & align your former white metal painted timing pointer with the former white painted mark on the crankshaft pulley. While on this carburetor side, loosen the 2 governor rod arm bolts on the front of the timing cover, (directly in front of the carburetor), & carefully remove the vertical governor rod arm that supports the horizontal governor rod that goes through this arm to the carburetor side of the governor, near the fan. Carefully slide & back out this horizontal rod from the governor -- gently lay this rod down in place, in front of the engine, while trying to keep the half-moon key in place, on the top of this shaft. Go to the magneto side and remove the 2 bolts securing the governor. Good time to pet the dog, have coffee & read this. (The next step won't work unless no. 1 piston is at TDC -- i.e., crank manually w/hand crank, to feel pressure in no. 1 spark plug hole before the white timing marks are aligned). (See note at end of this article if one has no hand crank & rotates engine w/fan -- not recommended -- fan blades may get bent this way). With your mirror & flashlight handy on the magneto side of the governor opening, carefully "jiggle" the governor forward towards the radiator until you can look through the magneto side of the governor opening with the mirror & see the dot on the rear of governor-ignition gear, and the 2 dots on the rear idler gear -- its a bit of a tight squeeze to "jiggle" the governor by the fan & shroud; but, have patience & take your time. Both gears may be covered with oil so its sometimes hard to see the small dots. Dots should be at about 10 to 11 o'clock when viewed from the magneto side, (rear to forward); but use a "Q-tip" to wipe all oil off of both gear dots, & also wipe all oil off of tops and rear side of all three (3) gear teeth on both gears -- 2 gear teeth on idler gear, & 1 gear tooth on governor gear. Carefully paint top & rear of all three (3) gear teeth with a "Q-tip" or small brush & white paint. Carefully remove paint from unwanted tops & rears of gear teeth if paint got on incorrect ones. Let paint dry abut 10 minutes. The governor gear has a spiral shape so when one aligns it to mesh with the idler gear, it will rotate slightly when one pushes the governor back into place. It may take 2 or 3 tries to verify alignment of the white painted gears, (single white governor gear tooth fitting between the 2 white idler gear teeth); but use the mirror, move cautiously with patience, & just do it even though the circular seal is hiding the marks. Slide governor into place one last time & use mirror & flashlight to verify the white meshing gear teeth marks. After gears are aligned, tighten governor in place with the 2 bolts. Posted by: H.L. Chauvin
Date: August 2001
Won't start - Coil? Part 1Hi, Sincerely hopes this may help someone someday! Cubs tend to refuse to run on weekends after Saturday afternoons, when the tractor part's places are closed. Had small radiator leak, had original radiator repaired, & re-installed 1948 repaired radiator. Went to start it, but it would barely fire enough to turn the engine to override the starter gear, & disengage the starter gear every time. Tried & tried several times on Saturday; but, would not start. Checked plugs after cranking -- all four (4) wet with gasoline & carburetor dripping gasoline after cranking. Removed coil wire, spark jumped 3/4". All four (4) plugs had what appeared to be good fire with hand crank & starter. Definitely serious Cub voodoo between the radiator & transmission. First, did nothing but think -- absolutely no action, no frustration -- mind had to be far over matter! Most important question? What had I touched to make it not start -- not the original magneto parts with the old 6 volt coil above; not the carburetor; but, had moved the separate old coil ballast resistor & mounting bar for the 6 V coil from an engine head bolt to the water outlet bolt. These wires had had been played with in the move & one (1) went to the coil. Went to this wonderful board to find a Cub coil one could buy on a Sunday, (for a 6 volt coil set up), for a 12 volt battery system with a built-in ballast resistor for the 12 volt coil -- i.e., a "Wells" , No. LU800 at Auto-Zone, $15.00, thus eliminating the old unsightly resistor with 50 coats of red paint. Been wanting to do this anyway, & $15.00 is a cheap try-to-fix operation these days. Removed the old coil and installed a new one in 5 minutes. Spark at plugs appeared the same; but, I felt so confident this component was all that I had touched that I did not even try the starter to start it. I choked it, turned 1/4 turn with crank -- un-choked it, turned another 1/4 turn with crank & it started right up & purred like a kitten. Now for the rest of the story: Which may pop many bubbles, including all of the written repair manuals, most trained mechanics, & most parts places! The old coil had so many coats of red paint on it, it was hard to read if it came over on the Nina, the Pinta, or the Santa Maria with Columbus, or previously with the Vikings; but, I remember the words of my Uncle, (born 1905), who said that every year thousands of coils & condensers were, & still are thrown away each week because when people change them out, they usually do not clean the corroded electrical connections, which is the primary cause of the malfunctioning of coils & condensers, & even points. To prove his point, I removed the new coil, cleaned the old red painted electrical connectors on the (+) & (-) side of the old red painted coil wires, reconnected the old malfunctioning 1492 red painted coil & resistor, & it started with 1/4 turn of the crank. (Will keep both old coil & resistor for a spare). When I bought my 1930 Model A Ford in 1956 for $25.00, it came with a fishing tackle box full of rusty coils & green corroded condensers which the former owner said some worked & some did not. After listening to my Uncle, cleaning the connections, & trying the entire tackle box full, they all worked -- still have them for spares, (in the same tackle box). Moral of the story: When all else fails, remove all electrical wires and clean the wire connectors. They can develop slight corrosion which can weaken the electrical performance of the old points, condensers, & coils systems of these vintage vehicles. After thorough cleaning, just for fun, try the old ones before throwing them away. Best wishes to everyone, H. L. Chauvin
Posted By: H.L. Chauvin
Date: May 10, 2004
Won't start - Coil? Part 2Please look at the May 10, 2004 message above on "Won't start" & please look at the paragraph starting with "Most important question?", which was asked on purpose as a hint to aid Cub owners to self-diagnose their own Cub problems because most engine malfunctions begin when one alters a mechanical or electrical condition either intentionally or unintentionally. (But a few problems just happen for unknown reasons). What did I tinker with? Think first, act second! My first hunch would be that: It is very likely that in removing your carburetor float, soldering it, re-installing it, & re-assembling your carburetor that something with this repair may have caused a change in performance. Also laying up a Cub engine for a year allows gasoline deposits to form in the fuel and air jet orifices; and allows corrosion to build up on points and wire connections. However, to save valuable time, go buy a $15.00 coil which means you may only be buying a spare, or maybe solving the problem -- go for it because time is so valuable. Most sincere best of luck & please share the solution experience -- we all learn something new each day. H. L. Chauvin
Making a Carburetor WrenchMade a Cub carburetor wrench for Nozzle Discharge Jet by soldering a 5/16" socket to a 1/2" diameter copper pipe, about 3" long with a copper elbow & a 1-1/2" long copper tube handle. (Wrench also works for a 1928-1931 Model A Ford carburetor). After assembling carburetor, if needed, un-solder socket from tube & place with socket set. Posted By: H.L. Chauvin
Repairing A Stripped CarburetorSome "J-B Weld" non-believers are going to frown on this fix, but I would never hesitate to try this before buying another carburetor. First, inspect threads in carburetor for "cleanliness" -- if dirty and full of Teflon tape or stick, pipe dope; buy a new shotgun barrel brass bore brush at Wal-Mart or similar Store, in size of .410 for a 410 shotgun. Clean stripped carburetor threads thoroughly with brush dipped in lacquer thinner or gasoline, using circular motion, and then clean threads again with lacquer thinner or gasoline on a Q-Tip until Q-Tip becomes white, and wipe dry with Q-tip -- do not touch the stripped threads with your fingers after they are cleaned -- oil from fingers are detrimental to this repair. (The above cleaning is the part of the work never done well by non-users and non-believers in epoxy repairs -- if epoxies wouldn't work, we wouldn't have any elderly movie stars with nice front teeth -- structural stress on teeth are far more intense than stress on a Cub carburetor gas line). Next get some J-B Weld & mix thoroughly, two (2)equal lengths of J-B Weld, (about 1" long each), mixed with a round tooth pick on a paper plate or similar items. Carefully and neatly apply J-B Weld to the carburetor stripped threads with a round tooth pick, and carefully and neatly apply J-B Weld to the brass male gas line fitting such that you see two (2) smooth J-B Weld surfaces, one (1) on all of the male threads and one (1) on all of the female stripped threads. (Don't get any in the carburetor screen inside the carburetor). Here's first the hardest part -- "Patience" -- allow the J-B Weld to set for about one (1) hour on both threads, depending on temperature & humidity. Next carefully align male, brass gas line fitting in hole and screw into carburetor -- then carefully unscrew male brass fitting -- then remove all J-B Weld from male brass fitting only. Here's the second hardest part -- "Patience" -- wait about 24 hours before trying the clean male brass fitting in the new J-B Weld carburetor threads. When trying the next day, if fitting feels too loose, clean J-B Weld carburetor threads again with Q-tip & repeat Steps 1, 2, & 3 above. What happen if this fails? Relax! Second try: Clean & fill the J-B Weld carburetor threads with J-B Weld, allow to dry 24 hours and make new threads in the J-B Weld carburetor threads with a machinist's tap. Not to be facetious, but J-B Weld fails at above 500 degrees F, so if your carburetor begin to approach 500 degrees don't panic & jump off of the tractor -- your brass carburetor fitting and jets will begin to collapse which will cause the engine to stop before the J-B Weld fails. I find the old time stick, plumbers pipe dope from hardware stores, (about 1/2" diameter x 4-1/2" long), applied to threads is hard to beat for non-leaking gas line fittings. Posted By: H.L. Chauvin
Repairing A Broken Idle TubeAlmost used part of a new brass 1930 Model A Ford "Zenith" carburetor jet, with larger orifice soldered shut and drilled out to match size of the Cub IH orifice. They sell for $3.00 or so from any of the many Model A Ford Parts Companies throughout the USA. Beats having to shell out $180.00 or so for a rebuilt IH carburetor. Suspected the IH carburetor Idle Tube had threads after receiving the carburetor isometric diagram sent by IH dealer. Very carefully tried pocket knife, Radio Shack screw drivers, & eyeglasses screw driver, but nothing moves easily -- Idle Tube probably been in there since 1948 -- 53 years or so of growing together with oxidation. As you mentioned, someone may have Idle tube removal suggestion! Patience. Posted By: H.L. Chauvin Top
Fuel Flow ProblemMy first guess is that the "in-line-fuel-filter" is holding air & not allowing enough fuel to siphon through it because of the gravity flow of the fuel as opposed to a fuel pumping system. Just tried a large "see through", in-line-fuel-filter on my cub this morning & the gravity flow system would not replace enough of the air in the filter; hence, the engine was stalling with the belly mower running, or running in 3rd gear. Removed it & it worked fine with the glass bowl & filter screen. I would try an IH glass bulb, definitely with a fine IH manufactured screen -- these work fine on gravity flow. Another former problem was that the old 1948 red rubber gas tank gasket was crumbling & partially clogging up the hole in the bottom of the tank -- cut out new gasket out of new gasket material, cleaned out tank cover, completely drained tank, poured gas back through a coffee filter & it works fine. When trying to clean inside of old carburetor jets, carburetor cleaner would not cut the old gray residue in the 1948 brass orifices. Took a round tooth pick, cut several notches in it at 45 degrees, wrapped fine steel wool around same, and passed it though jet -- shines inside like a new nickel. If you get a carburetor rebuild kit get an IH one -- the non-IH rebuild kits at non-IH dealers & on eBay have fewer essential parts for about the same price. Posted By: H.L. Chauvin Top
Carburetor SavedProceeded drilling out broken brass Idle Tube in top half of carburetor with 1/16" reverse drill bit 1st, 5/64" bit 2nd, and 3/32" drill bit last -- Idle Tube did not un-screw on any of the above while turning bits counter-clockwise -- really stuck -- can see threads where brass was removed -- used hand turned drill tool very cautiously so as not to ruin carburetor -- a real root canal operation! Float needle valve brass Cage, (screw), IH part no. 251 300 R21, sheared off when trying to unscrew -- really stuck also -- first removed all brass threads with "Dremel" tool grinder & then picked out threads with awl. (Could have used sharpened ice pick). Re-threaded with 5/16" x 24 teeth per inch (tpi) tap & restored damaged threads with J-B Weld & new brass Cage to form threads. Re-threaded butchered up threads at bottom of carburetor bowl with standard 1/8-27 NPT pipe tap, re-worked threads with J-B Weld, and installed new 1/8" plug. Cut & trimmed in-side diameter of new carburetor to intake manifold gasket, (supplied with carburetor re-build kit), where it protruded about 1/32" all around -- this means 1/16" smaller orifice causing turbulence & restriction in fuel mixture entering engine. (For example, a 1" diameter intake is .785 square inches, & a 7/8" diameter intake is .653 square inches, which is only 83% the size of the above 7/8" intake -- quite a reduction in intake & fuel entering the engine -- similar to running engine with throttle partially closed.) Cut new washer shaped felts to place on sides of throttle shaft to prevent raw air from entering the carburetor after fuel is mixed at the venturi. Filed parts of top half of carburetor where it meets gasket between top & bottom, (where screws occur), so adjoining halfs fit nearly flush at the gasket. (Place 3 corner file over 2 screw holes at a time and apply pressure on file equidistant between screw holes to maintain a level surface.) The gorilla mechanic who removed the carburetor once or twice hit the carburetor on the side with a big file, leaving file marks on the side of the soft metal carburetor -- took a file and removed file marks and polished entire carburetor on a wire wheel. Filed burrs off of all interior & exterior screws where improper sized screw drivers were used with great force for 50+ years. Carburetor looks shiny and new as if out of a new box. Posted By: H.L. Chauvin Top
Carburetor Leaks & AdjustmentsLeaking threads: Everyone today uses teflon tape on new threaded fittings. Teflon is a lubricant that allows one to tighten fittings to full torque because of the sliding lubricating action; however, with vintage vehicles that have worn out threads, teflon does not "seal" damaged threads. One should step back 30 years & go to the hardware store & ask for a 3" long x 5/8" diameter "stick" of pipe sealer, (pipe dope) -- its good for water pipes & gasoline fittings. Put it on the female fitting with a small screw driver and put it on the male threads with your finger. Screw the connection, then take it apart & wipe off the excess so this excess dope does not later clog the carburetor, but leave sealer in thread recesses to "seal" the joints. Tightening carburetor fittings: Use only 2 fingers on a screw driver & nut driver & fit snug -- grasping with whole hand is too much. Fuel adjustment: The Cub carburetor has 2 fuel adjustments to make it run rich or lean, & both are part of the float mechanism which is hidden within the carburetor. Take an envelope or manila folder about 6" long and draw two (2) 6" long pencil lines parallel to a straight edge of the envelope, one at 1-13/32" above the straight edge, & one at 3/16" above the first line or 1-19/32" above the straight edge. Turn the carburetor upside down with the gasket on it & very carefully adjust the metal part of the float between the float body and float pin such that the float height will be 1-13/32". (Remove the float from the float pin to make all adjustment so as not to damage the fuel float valve). Then turn the carburetor over in its normal position & adjust the vertical small tab on the other side of the float pin such that the float drops down 3/16". Now set carburetor in place after assembly & check fuel level with a clear plastic tube and barbed brass fitting screwed into the bottom of the carburetor bowl. Fuel level should be 9/16" to 5/8" below top of carburetor gasket. (If the float ever leaked & was repaired with solder, it will be heavier & sink deeper, thus raising the carburetor bowl fuel level, thus causing the engine to run rich, foul plugs with black soot, thinning oil on cylinder walls and creating smoke. Suggestion: Temporarily re-adjust float to 9/16" to 5/8", but buy a new float to get these hidden settings as close to perfect as possible. Gently turn carburetor over to "listen" to make sure float is droping, & remove bottom bowl screw to "see" if float is dropping and functioning. Idle screw: Turn inward until lightly seated & back off one full turn -- start engine, run for about 5 minutes and fine tune idle adjustment screw and RPM adjustment screw. Suggestion: Go to small engine parts place or similar & buy a plastic shut-off valve to cut off the fuel to the carburetor -- (about $3.50). Every time you finish with the cub for the day, shut off the fuel & let it run out of gas. The carburetor will never "gum-up" with no gas in it. Next try to get a "see-through" gas filter from J. C. Whitney or similar & set vertical between gas tank & carburetor. With an added gasoline filter & shut-off valve your next carburetor re-build should be about two (2) weeks after the 5,000 year old pharohs return to the Egyptian pyramids to plant the wheat left in their tombs. Best wishes,
H. L. Chauvin
Carburetor Float ProblemAs you have already recognized, the float is not closing the fuel float needle valve when the carburetor is assembled because the gas level is rising in the bowl above the top of the discharge nozzle. But, when you close the needle valve with your thumb it does its job & stops the fuel flow. Great observation. Because someone may have already bent the tang on the float, using manufacturer's measurements may not help all of the time. Also, on rare occasions, floats leak gas and they sink: Place the float in a small pot of boiling water -- if bubbles come out of the float, it leaks and the hole or seam needs to be soldered after th float has all of the gas removed by setting it in the sun for a day or so. Next, check to see if float can move up and down "freely" without rubbing on sides or front, or binding on its axis. If float moves freely, and doesn't sink: Buy a 1/8" NPT brass plug with a brass tube nozzle to connect a 1/4" clear plastic tube about 8" long, remove 1/8" plug on bottom of bowl, and install brass plug with tube. Put the tube on the nozzle and curve tube upward like a horseshoe so you can now see just how high the fuel is rising in the bowl -- the fuel level should be about 5/8" below the gasket between the top and lower half of the bowl with the carburetor installed on the engine -- but, first turn carburetor upside down to insure that the metal float tang is dead level with the joint between the upper and lower half when it touches and seats the needle valve -- then adjust float up or down to get the 5/8" gas level reading in the bowl. If this is done, there is no way the fuel can climb up and out of the discharge nozzle. Carburetor Leak When one has a used tractor, no telling what was done to the carburetor & float in the past by amateurs, and also with the cheap parts sold for carburetor rebuild kits -- your question can have difficult answers. I'm a firm believer that if Napoleon Bonaparte would have bought a Cub when he was a Corporal in the army in the 1700's, (and if he would still be here today with the same Cub), and he would have only gently cleaned his carburetor every 20 years, all of the original parts would still be fine shape except for new gaskets and for new seals on both the throttle and choke shafts. Could be you have several problems: Leaking float -- place float boiling water to see if bubbles come out -- if so, it leaks gasoline & sinks & does not close the float valve -- dry float in sun all day & solder float leak hole or replace float. Leaking float valve -- with carburetor apart, push up on float valve with float "in place", fill gas line with gas and see if float valve leaks when gas line is full -- check metal tang on float to see if it makes good firm contact with float valve -- make sure float is not binding on sides of carburetor or elsewhere -- could be a replacement valve that does not fit original float valve cage or vise versa -- or someone in the past trying to lap a float valve in a cage with valve grinding compound & messing it up -- lots of times its dirt by-passing a faulty filter & entering the carburetor float valve, causing the float valve not to seat -- if float valve leaks, get new float valve & cage -- if float tang needs adjustment, adjust same. Float adjustment -- hook up transparent tube, (shaped like horseshoe, maybe 6" long), to a screw-in plug on carburetor bottom, fill carburetor with gas to see gas level inside tube -- should be at same level as gas inside carburetor when float valve is closed & repaired -- gas level in carburetor should be 9/16" - 5/8" below joint between carburetor top & bottom -- carefully adjust float to keep gas at level specified above. Hope this helps a little. At least you see that both the float and float valve have to function properly to maintain gas at the proper level Posted By: H.L. Chauvin Top
Is It The Starter?Hi, It's always difficult to guess what's going on when not being able to see what one has, but maybe try to isolate the problem by first removing the starter switch entirely, and then: Turn the ignition switch "on", (after you positively know the transmission in neutral), and touch the brass button on top of the starter with the battery cable -- if the starter turns, the switch may be malfunctioning and not making proper contact. New parts are not always free of defects. If the starter does not turn, the starter may be malfunctioning, or; The battery cable may not be conducting current to the starter switch. Sometimes the cable connectors at one end or both ends of the battery cables get corroded, or at the battery connection, and just stop conducting current at the oddest times and one thinks its time to junk the thing when it's only a simple corroded cable matter. It sometimes happens to the best! Hope this helps, H. L. Chauvin
Posted By: H. L. Chauvin Date: Friday, 15 August 2003, at 12:27 a.m.
Stripped Carburetor to Manifold BoltsOn your very keen "won't crank" message below concerning a leaking carburetor gasket etc. & cranking, it reminded me of a recent fix for my stripped, rear carburetor to manifold bolt which may help somebody. On the front, (radiator), side of the carburetor, if the carburetor threads are stripped, its easy to drill out the carburetor threads & place a matching nut under the carburetor flange to tighten the carburetor to the manifold, as was done often on many vintage engines. On the rear carburetor flange, the previous owner(s) had filled his stripped, threaded carburetor flange hole & made "make-shift" threads with "Liquid Steel" or some similar material in a tube which did not last. When one gets a longer bolt to try to fit a nut on the rear carburetor to manifol bolt, one notices that the bolt threads almost rub against the carburetor; hence a nut will not fit. What to do? Get the longer bolt; get about three (3) matching nuts in case some are ruined; drill out the damaged carburetor threads; get a vice grip pliers & hold one of the flat sides of the nut on an emery wheel & grind this side of the nut until one has about 0.016" left between this flat outside of the ground down nut & the threads. Try the fitting of this nut. After installing the carburetor to manifold gasket & the front carburetor flange bolt, hold the special machined nut under the carburetor flange hole with a flat head screw driver, place the rear bolt through the manifold flange & through the carburetor flange, & thread the bolt through the nut & tighten. Hope this helps somebody one day.
H. L. Chauvin
Posted By: H.L. Chauvin Date: Monday, 31 May 2004, at 11:25 p.m.
Governor RockshaftLoose Rotational Play: Hi, Hope this may help somebody someday. This afternoon I checked my governor rockshaft arm which is located on the carburetor side of the engine & connected to the carburetor throttle with a rod & adjustable yoke & yoke pin at the governor rockshaft arm. After disconnecfting the throttle shaft yoke by removing the yoke pin, in rotating the rockshaft arm clockwise and counterclockwise, the rockshaft arm could move back & forth, (rotate), with about 5/16", (0.3125") free moving loose play, while in the vicinity of the 7 o'clock position. The two (2) rockshaft bracket bolts were removed & the rockshaft rod was pulled straight out of the governor spring coupling for investigation. It was observed that the rotating loose play occurred in the recess in the coupling where the rockshaft rod key engaged in the coupling. How to tighten this connection to try to reduce the loose play: Maybe some sort of shim? The yoke pin hole in the rockshaft arm was about 2-5/16", (2.3125") from the center of the rockshaft rod; however, on the other end of the rod, the top of the key in the rockshaft rod was only about 3/16", (0.1875") from the center of the rockshaft rod. If the yoke pin hole can rotate 5/16",(0.3125") at a distance of 2-5/16",(2.3125") from the rod center, how much free play (X") in inches is occurring in the rockshaft coupling where the top of the key is only about 3/16", ((0.1875") from the center of the rod? 0.3125"/2.3125" = X"/0.1875"; hence, X" = X" x 2.3125" = 0.3125" x 0.1875"; hence X" = 0.0585937"/2.3125"; hence X = 0.025"; hence a shim on one side of the key would have to be about 25/1000ths, & a shim on both sides of the key would have to be about 12-1/2/thousanths, (0.0125") of an inch. The last time I went into an auto parts store and asked the gentleman if he had any "shim stock, brass or steel", I felt like I had just pulled up to a crowded gas station in a covered wagon & asked the person behind the counter if he had any axle grease & horse shoe nails; however, what to use for shim stock? My wife had some in the kitchen. To make a long story short, I tore off some aluminum foil, checked it with a micrometer, & carefully wrapped the coupling end of the rockshaft rod tightly with seven (7) layers of aluminum foil, carefully tightnening the foil on both sides of the key with the back of my fingernail. Next inserted the foil wrapped rod & key into the coupling, re-installed the rockshaft bracket & found that I had 1/16" (0.0625") of rotating loose play as opposed to 5/16", (0.3125"), close to 1/3" play. The governor was easy to adjust to gain RPM on every notch of the throttle quadrant. Like brass, aluminum foil has some compressive strength. Sincerely,
H. L. Chauvin
Posted by: H. L. Chauvin (dpc6682074187.direcpc.com) Date: Monday, 31 May 2004, at 12:51 a.m.
New and Used PartsThe Answer: (This particular series is in response to one particular poster and is a continuation of the saga. The reason it is here, is because of the value of the information as well as the humour I guess. Sometimes Henry would respond rather promptly and with a number of posts. At that time one did not edit one's post easily if at all possible) Hi, If the after-market PTO shafts presently offered are of soft steel, and a new Case/IH is not available, it appears that a good used shaft will last longer. Mine, (I'm sure an original 1948 cub PTO shaft), even though worn, could have been re-used except for the broken weld on the welded sheave connection on the rear end of the PTO shaft. H. L. Chauvin Hi, I just called the company you mentioned to ask the question of quality of new vs. used Cub PTO parts. They say the new PTO parts they offer are just as good in quality, metal material, & workmanship as the former used PTO parts; & that the difference between new and used PTO parts is that the used parts have some wear on them. He also said nobody ever compained to them about their after-market PTO parts. It is very possible that some of these after-market parts are as good as the former Cub parts of the 1940's & 1950's -- probably just depends who makes them -- today with computerized lathe & shaper machinery they can be mass produced almost as fast as a copy machine, thus reducing cost. It's educational & interesting to hear one's actual experiences on critical PTO & similar moving parts that can wear easily & quickly. H. L. Chauvin Just went to http://www.casetractor.com/ to browse prices & shipping costs, & see where one may order Farmall Cub parts on line. Had no idea so many small intricate Cub parts are still available for older Farmall Cubs, if one has the part numbers from a Cub parts catalog to identify them on line. As John said, some of these PTO parts are still made by Case/IH, & they are offered through Case/IH dealers, etc. Also, some independent dealers & Case/IH dealers can obtain and offer Case/IH parts as well as their own after-market parts which were not provided by Case/IH. One difference between Case/IH parts and after-market parts is price -- after-market parts being less expensive -- sometimes half price. In testing my old former 1948 Farmall PTO parts with a file, the steel is tempered extremely hard & performed well for so many years. The only part I could not find by Case/IH was a PTO shaft; however, these are offered as after-market by several vendors. (My PTO shaft has to be changed out because it was welded by a former gorilla owner/mechanic to a Wood's mower sheave spline -- the weld broke years ago -- the gorilla mechanic could not even weld correctly). In any "case", (no pun intended), it may just be a good idea to stay with the reputation of Case/IH parts, if Case/IH parts are available. Has anyone had experience with an after-market PTO shaft?
H. L. Chauvin