49 cub starter/magneto

[Eugene]

I did get a nice blue arc to the oil canister with every crank. I did have the ignition wire disconnected from the mag housing during the test.

Also my cub has been exposed to rain for couple days while at camp. What am I missing?

Moisture inside the distributor cap. Remove the distributor cap and dry out the interior.

[lazyuniondriver]

This is getting a bit harder as you have been working on more than 1 component system at a time. Since we now know your ignition system is working, let's focus on the spark distribution system.

The spark distribution system is compromised of the spinning rotor the distributor cap and the spark plug wires ending at the spark plugs. As the others have said, start by examining your distributor cap for moisture or cracks. Examine the rotor for arcing or pitting or signs of corrosion on the metal parts.

If the cap and rotor passed inspection, check your high tension leads for cuts, cracks, abrasions, and dry rot. Finally, remove a spark plug and reconnect the high tension lead to it, ground it and crank to determine if your getting spark. If you have a spare spark plug, you can use one just make sure the plug is grounded.

Don't connect that kill switch wire your to the magneto just yet, we don't want to rule out faulty wiring or a bad switch. Let's get the tractor running before we reconnect that magneto kill switch wire

[firetech]

Update....
I tested spark right at spark plug and I'm getting spark right at the plug. I guess I must have carb problems? I did clean the carb making sure jet was clear and everything seemed in order but is there something I could be missing?

[Eugene]

Wow. How long has the tractor been sitting since it last ran? Could someone have messed with the tractor? Did you remove more than one spark plug wire at a time from the magneto's distributor or spark plugs?

At this point I would go with a systematic approach to the no start problem. I would do a 100% engine tune up, starting with compression tests. Then move to the ignition and lastly fuel/carburetion.

[lazyuniondriver]

Yes, if you are getting a good spark to all 4 plugs, you could very well have a fuel issue.

Rule # 1 of mechanicing... Go back to what you messed with last.

Recheck your work on the carb. If gas is dripping out it may have an issue you overlooked.

As insurance before starting at the carb, make sure you have spark at all 4 plugs. It would probably be best to pull all of them, clean them, then check each one individually with its own high tension lead for a good spark as you crank it over.

Don't attach that kill switch wire yet. A combination of factors are involved now so we'll try and eliminate as many of the variables as we can.

[pm_wells]

[quote="lazyuniondriver

Rule # 1 of mechanicing... Go back to what you messed with last.

I have to admit I have done some of this Not saying anyone here does this, didn't know Mechanicing meant this.

Farm Mechanic
A person, mechanically inclined, who fixes machines without regard for their 'stated operations' or 'proper repair procedures'.

Farm Mechanics must be used to repair machines which cannot be retreived through conventional means - such as machines which have gone beyond their stated tolerences, and would need to be 're-milled' to continue service... ( cracked engine blocks, shattered transmissions and differentials )...

The repairs seek to retreive a significant percentage of the machine's original function, while costing little, requiring few tools ( Farm Tools ), and being generally quicker ( but less 'reliable') than traditional repair methods.

The safety and 'transferability of operation' of the machine are ignored - once repaired in this way, one must continue to repair the mahcine in this way, and its operation might not be apparent or possible for those unfarmiliar with the repairs...

A typical Farm Mechanic's tools include pliers, vice-grips, a hammer, a larger hammer, a crowbar, JB Weld, bailing wire, an AC arc welder, a pipe wrench, duct tape, a farm jack, plumber's strapping, and 4 inch framing nails...
John's tractor threw the #4 connecting rod out through the bottom of the oil pan... the repair estimate was $6000, but the tractor was only worth $1200 - so John Farm Mechanic'd it back together, by welding the oil pan and modifying parts from another machine to fit. It now must idle 10 minutes when it starts before that piston begins to work, and it made a strange sound, but it drove forward and continues to work...

[firetech]

I will do as you mentioned and test all 4 plugs for spark before continuing. If it works then I guess will move to the carb for attempt #2. I'm glad that I did get spark because that should be the bulk of my problems. Wish me luck!

[Rudi]

Since you are getting spark at the plug then your cap should be fine - but double check just in case there is a little moisture in the cap. Spray with WD-40 (Water Displacement formula #40) as a precaution and a PM measure.

Remember for a Cub to start you need all 4 specifics present.

Fuel
Spark
Compression
Air

You have Spark, I am assuming you have compression and I am assuming that you have sufficient air being mixed with the fuel. You checked the metering jet so you are getting fuel but not a start situation. This is where the problem lies......

Update....
I tested spark right at spark plug and I'm getting spark right at the plug. I guess I must have carb problems? I did clean the carb making sure jet was clear and everything seemed in order but is there something I could be missing?

Well for starters:

Also my cub has been exposed to rain for couple days while at camp.

Condensation in the carb is a good way to provide a no start situation. Plugs don't fire too well on water.

I am getting what looks like gas spilling from carb when trying to start it.

Flooding it. Let it dry out a bit.

Check for condensation - sometimes visible on the side of the carb. Usually it is apparent when you take the carb apart. A whitish deposit will be present in the bowl indicating that water has sat in it for a bit (provided it was long enough). Yeah, been through this with Ellie this year. She sat for 6 months before I could get to her.

[lazyuniondriver]

[quote="lazyuniondriver

Rule # 1 of mechanicing... Go back to what you messed with last.

Maybe I misspelled mechanicing. Maybe its mechanic-ing, I don't know.

Anyhow, I learned that early on... If something was working, you "fixed" it and it no longer works, the problem will always be what you had you hands on last.

Example. I purchased a brand new chromium plated gas cap for my 25 year old American made motorcycle. Two miles from the house, it came to a screeching stop. Just as if somebody had turned the gas off or it had run out of fuel. A 1,000,000 things begin running through my mind what would cause the problem. Did I forget to turn on the gas, was I out of gas?

Suddenly I remembered the new chromium plated cap staring me in the face.
I removed the gas cap and with a big whoosh about a gallon of air rushed into the tank.

I started it right up and rode away. It wasn't a lesson learned, it was s lesson I had already learned and almost forgot.

[bythepond88]

Double check that the plug wires are not mixed up, and double check that the magneto is timed correctly.

[firetech]

final update.....full story

let me start by saying thank you soooo much for all your imput and information - its nice to see wonderful people willing to help out complete strangers.

Started and played around at camp for 20 mins. Parked cub and left. Returned 5 days later (rain every day) to bring cub home for winter. Could not start it - killed battery(never had much luck with hand crank) so I left. Returned with fresh battery and after 20 mins killed battery, starter, and fuel was spilling out of carb. Never noticed gas from carb before. Manually loaded cub on to trailer and drove home. At home dismantled carb ( now twice) and every orfice and plug is clean, float is operational and within specs that I have and all seems ok. Cleaned rotor and cap ( dry and shiney now) cleaned plugs and again all seems in order. I am getting spark at the plug (each one tested) I don't know what constitutes a "good" spark but none the less there is spark. Still I am getting fuel spilling from the front side of carb(attaches to air breather) while I try to start it. attempted choke open, closed, and partial. have even attempted fuel directly into plug hole and ether sprayed into carb opening and also attempted ether sprayed up the cylinder opening just above the carb ( carb removed). My hand might be broken from the million cranks with the hand crank. So to finish my story I am putting the for sale sign on my little red machine and its sad but I have lost the little patience I had left.

[lazyuniondriver]

Oh yes, mechanic-ing can sure be frustrating at times. But on the flip side, what a good feeling when you pull its leash and that cub springs to life.

Give it a week or two, you'll get the urge to tinker with it again, not wanting to let a simple machine get the best of you.

A combination of circumstances ihas unfortunately got the upperhand at the moment.

Next week, put the charger on it, pick up a new set of plugs and start from scratch with a fresh slate.

[Eugene]

Give it a week or two, you'll get the urge to tinker with it again, not wanting to let a simple machine get the best of you.

Yup. Give it some time. I don't think there is anything seriously wrong since the tractor was running 5 days previous.

Since you mentioned spark several times. Have you carefully checked the ignition system other than the fact that it sparks? Timing? Correct wiring? Rotor slipped gear tooth/teeth? Etc.?

Systematic approach to the problem. Carefully check each system, one at a time.

[firetech]

total indepth verification I have not done but wiring should not be an issue - was running fine prior, I did not time it but I did carefully listen to the mag click while watching the fan belt notch meeting up with alignment mark like when doing a mag re-time and that seemed good. jst a question but if I have spark should I not get something happening with gas directly in cylinder? Is there a way to mimic gas getting to cylinder? After all this testing the plugs are dry - like fuel not reaching cylinder and just pouring out carb. Another question is looks like the governer plate that is above carb orfice next to manifold is in the closed position - is this right? how does fuel reach the cylinder if the hole to the intake manifold is blocked. Pretty sure I am more confused then I've ever been.

[lazyuniondriver]

Pouring gas into a cylinder then capping it with a plug seldom produces anything productive.

Remember a gasoline/air mixture is brewed in the carburator before being inhaled into the cylinders then lit.

Pure air will not burn nor will liquid gasoline, it takes a proper mixture of the two to support combustion. Ether should have lit it up for a second but if your battery was already low when you tried that, your spark may have been insufficient at that point.

If the speed control lever is advanced 1/3 to 1/2 ahead for starting, the throttle plate or butterfly should be open, not closed in preparation for starting. I don't think this is an issue as this was a running tractor a week or so ago and you know how to start your tractor.

At this point in your journey, from what you have reported I feel there may have been nothing wrong except moisture under or on top the cap and on the plug wires.

Through the learning process you jumped around quite a bit, touching bases in both fuel and electric components, possibly getting them out of sync so to speak.

Like I wrote earlier, start over with a charged battery and new plugs. Attempt a cold start with no choke. If it doesn't start in 5 or 10 seconds of cranking or the time it normally took to start, its not gonna start so stop before flooding the carb or killing the battery and we'll continue troubleshooting at that time.