Acquired a 48 cub!!

[Glen]

Hi,
A coil doesn't quit often, if it is good quality.
With a cap, the contacts get burned, or the center contact can wear out. Sometimes a cap can crack, then it needs replacing if the spark is following the crack and shorting out when the engine is running.
When you take the plate with the rotor off the magneto, it is good to note where the rotor is turned, and don't turn the engine while it is off, so you don't get it out of time from where it was.
If you took the rotor and drive gear out of the cover to grease them, the timing marks need to be aligned on the rotor and gear, like Stan said above. Notice if they were aligned when you took the cover off.

[Rjpoog1989]

Well despite my lack of machanical knowledge, I'm making progress. I had the cub started, it ran about 30 seconds then shut off. Tried to restart and it ran about 15 seconds, that's all it will do no, run 15 seconds then stop. I need to replace the gasket in that gas strainer hickey under the tank so gas stops leaking all over the place. Can't do that till Friday. In the meantime, what should I be looking at?

[Bob McCarty]

That sounds like poor fuel flow. Turn off the gas at the sediment bowl, remove the drain plug from the bottom of the carb. Turn the gas back on and see if you get a steady stream of gas (almost pencil diameter in size). If not, you have gunk in the sediment bowl, the gas inlet screen, or perhaps the needle valve.

Bob

[Glen]

Hi,
Glad you are making progress.
The choke has to be adjusted right when the engine is cold, it has to be partly on until the engine warms up some, or the engine could stop.
If that is not it, it could be a fuel problem making the engine stop after 30 seconds running. Check the fuel flow, it needs a good stream of gas into the carburetor. Remove the drain plug on the bottom of the carb, and catch the gas in a clean can, there should be lots of gas come out first, that was in the bowl, then the flow of gas through the line will come in, it should be a steady flow, check it for 30 seconds.
You said the fuel strainer leaks, it needs cleaning, and there should be a fine screen in it, above the gasket for the glass bowl.
Look in the gas tank with a light and see if the inlet into the fuel strainer is open, sometimes they get plugged from something in the gas tank, be careful not to make any sparks.
There is a screen in the inlet of the carburetor too that could be plugged some and need cleaning.
The main jet in the carb could need cleaning too, could be any of these, or more than one.
Here is a pic of where the main jet is, it's the brass hex head part on the lower side of the carb. It screws out, remove it and run a small wire in the hole in the end of the jet, blow it out with air too. The gasket might not seal again if it is old. TM Tractor has new ones, here is a listing below.
Here are pics from TM Tractor too.

http://www.tmtractor.com/new/fl/4873fp.htm

http://www.tmtractor.com/new/fl/426fp.htm

http://www.tmtractor.com/new/fl/235fp.htm

[staninlowerAL]

Remove the drain plug on the carb or the fuel line at the carb connection and catch about 8 to 10 oz of fuel in a container. If the flow is unrestricted during the time it's flowing you probably have some trash/foreign material in the carb. If the flow slows or almost stops during the flow test you have a restriction in the tank/fuel shut off valve/filter screen or any in-line filter that may have been added. If you have an added filter make sure it is rated for a gravity flow system; an inline filter for a pressure system will not work satisfactorily. When you solve any flow/delivery problems to the carb, if there is still a flow problem, remove the main jet from the carb and use a small soft wire like a 22 ga copper telephone wire to ensure the jet orifices are clean. Spray with carb cleaner and compressed air to help clean. The OEM IH carb had a fine mesh screen in the inlet where the fuel line connects to the carb. Check that it's not plugged or restricted with crud from the tank/fuel delivery system. If you still have fuel delivery problems you may have to remove and separate the two carb sections. After removing the 5 screws, remember to pull the top straight apart to keep from damaging the idle jet tube. The idle jet is at the upper end of the tube and very small, about the size of a fine screen wire strand. Don't attempt to "rod" it out, use carb cleaner and compressed air to flush and blow it out from both directions. You will most likely need a new gasket. Look for free movement on the float, carefully remove the needle valve and flush/clean all the internal surfaces. IH carb is a fixed jet and the only internal adjustment is the air flow screw which should be about 1.5 turns open from fully closed for starters. Check the float drop and the seal on the needle valve while it is accessible. This is pretty much what needs to be done to clean and adjust it to run.
EDIT: Bob and Glen type faster that me and I talk too much!! Stan

[Rjpoog1989]

Thanks for the quick replies! I appreciate everyone's help!!! I will update when I get somewhere with it.

[Eugene]

When you start the fuel flow from the tank do you back the sediment bowl shut off valve to the stop? Not partially open the valve?

[Glen]

Hi,
Looks like Bob, Stan, and I were writing at about the same time above.

[staninlowerAL]

When you start the fuel flow from the tank do you back the sediment bowl shut off valve to the stop? Not partially open the valve?

Not only will you not get a "full flow" but the valve is double seated. That is, it is supposed to seal in the full open or full closed position. Minimizes seepage around the valve stem. (See, I can do a short answer.)

[coppersmythe]

one of my recent experiences with similar symptoms ( run a while, stop . run 20 seconds ,stop , runs rough ) . gasket between the glass bowl and the shutoff valve housing was just leaking enough to cause the problem . new gasket , problem gone . coppersmythe............ PS: 84 degrees today , 90% humidity . we had to turn on the central air . got a buddy up in the UP of Michigan , said it was 14 degrees today and piles of snow around his house , brrrrr.

[Glen]

Hi,
coppersmythe, that sounds warm, hope it warms up in other places too.

Rjpoog1989, if you can't get a good gas flow from the gas tank, I think someone wrote before that there was junk in his fuel strainer, and he couldn't get it out without removing the strainer and taking it apart.

[Rjpoog1989]

Yesterday I had the tractor running for about a minute, maybe more. It was still leaking gas so I shut it off. Today, I got a new gasket for the sediment bowl and it's not leaking any more. I also drained and refilled coolant. When I tried to stay the tractor today it wouldn't start at all. It's a lot colder today though, bout 25 degrees instead of 60...

[Rjpoog1989]

I tried messing around with the cub a bit today with it being warmer outside. Still no luck, I noticed the plugs were pretty fouled up so I replaced. Nothing... it's getting good fuel to the carb, but I'm not sure past that. I called a guy up the road who has an antique tractor restoration business, I'm hoping he can give me some insight.

[Rjpoog1989]

So being it was so nice today I decided to piddle around with the tractor. Been reading about carburetors thinking it was a fuel issue, and there may still be one. The other day I bought a test light to see I still had power, and points opening and closing as they should. That's what was making me believe it was fuel. I'm scared to take apart the carb, plus I don't have a rebuild kit. Out of shear boredom I decided to try retiming the magneto. I also fully charged the battery.

WhaLa!!! She runs!!!

Ok so she starts fine with the choke lever fully out (towards me). I'm assuming that's full choke. At half choke, still good. With the lever fully in it stalls, every time. At half choke it doesn't really sound like half choke. I really don't know what it's supposed to sound like though, it's been 10 or more years since I've heard it run correctly and I was like 16 at the time. Also, the oil pressure gauge shows nothing, I know the pump is working though because the filter had oil all over it when it was completely dry before running. I did dump oil down the tube pictured to prime the pump before I started it a week or so ago. I do want to change the oil asap though cuz it's black and who knows how long it's been in there... I'll see about a new gauge from IH dealer.

[Glen]

Hi,
Glad that it runs.
The engine needs the choke on to start, if it is cold, and partly on as it warms up. You have to adjust it to where the engine runs best. It might stall if you don't use enough choke when it is cold. The Cub owner's manual tells about choke use in the starting the engine pages.
If it won't run when warm without the choke on, it sounds like the carburetor main jet needs cleaning. If it is plugged, the engine probably won't run without the choke on. Look above at my post on Mar. 8, I wrote how to clean the main jet, and there is a pic of where it is, it is easy to do.
The fuel should freely run out the hole for the jet too, if it doesn't something is plugged and needs cleaning inside the carb, or farther up from the carb.
The pic shows the choke in the fully open position, look at yours and see if it is working the same way. The choke rod should be fully in when the choke is open.
Shut off the fuel valve before removing the jet, fuel should run out as long as it is out, if you take it out with the valve on.
Case IH does not have the lower pressure oil gauge for a Cub, that I know of, only a 75 lb gauge. These don't work too good on a Cub, the hand doesn't go up much on the dial.
TM Tractor has gauges that are for Cubs, it says they had them made for them. Look and see if you want one, there are different styles that IH used for different years. I don't know which of the first 2 yours has, or had. The 3rd one below has numbers.

http://www.tmtractor.com/new/en/2645fp.htm

http://www.tmtractor.com/new/en/5732fp.htm

http://www.tmtractor.com/new/en/3291fp.htm