Farmall F20 Not Starting

Thank you in advance for your help with this. My dad fully restored this tractor and he has passed a few months ago so some of this I am trying to learn to make sure the family tractors keep running as smooth as they always have. The 1937 Farmall F20 is not starting and I am not sure what all I can check to see what is going on. This tractor has always started on 2 or 3 cranks and now it's not starting at all. It was outside when it did a small rain one day but the magneto was covered.

1. I cleaned the spark plugs. They didn't appear damaged but they were black. When I am cranking the tractor fuel will drip out the weeping hole of the carburetor. If I turn the choke on and I crank it the fuel will shoot out of the weeping hole. I am not sure how normal it is to have it shoot out the way it did in a fast stream.

I do plan to check to see if there is spark by undoing one of the spark plugs and putting it near the motor to see if it does a hot spark. If it does not does that mean the magneto is messed up? If so, what are the next steps in diagnosing the magneto so it's fixed?

If the tractor does a hot spark but it's not turning the engine over I'd assume the next step would be to replace the spark plugs. Would there be anything else that could be causing this?

I am guessing it's something electrical because the tractor never turns over but I do hear the click sound that comes from the magneto when you're cranking the tractor. I believe it's the sound you want to make sure it's doing to ensure it's a safer crank to where it won't kick back on you.

very first thing is to check for spark as you said. all it could be is the points get a film on them from sitting. use a point file or some
emery and clean them check the gap to .013 any magneto tractor starts very easy when tuned up. the spark plugs are last on the list and the
chance of 4 plugs not firing is close to nil. and yes you need to here the click or it will kick you. you will hear and see that BLUE spark
jump the plug gap. and yes normall for gas to drip from carb when choking.

Mag points are just as likely to get corrosion and a non conducting film as regular ignition. I am not sure what mag you have, but taking it apart to
get at the points requires keeping the mag gears in the same timing they were. The rotor must be where it was, no rotating the engine. Clean and gap
those points. .013" I think. Jim

E4 and F4 ihc mags all you need to do is remove the advance cover off the back and points are right there, nothing to take apart. it should have the F4 mag

If you're not familiar with the tractor, do you know where the shut
off lever is up by the steering wheel? It has to be in the "on" position.
My F20 would start if you accidentally turned the crank.
No speed required, just roll it up on impulse and flip it.
It sometimes started trying to roll it up on impulse when warm.
The points do need to be clean and working as said.

Do check the spark at each wire, at the plug end.

The clacking sound is the impulse spring, which winds up and releases to spin the mag fast enough to spark at cranking speed.

While you are checking the spark, with the plug wires disconnected and the plugs in, you should be able to feel each cylinder come up on compression, feel the resistance against the crank. If one turns through with no resistance, there may be a stuck valve.

It is concerning that you see fuel blow out the drain vent with the choke on. That could be a stuck valve, or just the engine kicking back of a compression stroke, just something to check.

The lever that controls the mag must be down to the 3 o'clock position for mine to start. I have been going to label it as the on position because I only start it occasionally and I don't always leave it in the same position after shut down. My F 20 will not start using the proper starting technique that is prescribed by the YT faithful. I can start it using a slow, quarter turn crank from 12 to 3 o'clock, using one hand while the other is holding the choke rod.

As said earlier I bet you just don't have the spark retard lever on steering wheel in the right position. Now the tractor is flooded. Warning!!! do not spin the crank round and round. Those cranks come off
and swing up and hit you in the mouth. Don't ask me how I know. I think before you do anything, you should try pull starting it with another tractor. Then you will learn if the spark lever needs to be up or
down for running. Your Dad new position of the spark lever for starting. It is somewhere between full up and full down. You will have to learn that trick with practice. Sorry for the loss of your Dad.
They are special.

Thank you for the feedback. I have never messed with a magneto so bare with me. How will I know if it's at the .013? My dad fully restored the tractor and it's never kicked back at all so I assume the timing is good right now, but if I am messing with the magneto I am not sure if I will mess that up? Also, how would I get access to the points to clean those off?

Thank you. How would I take the magneto apart to clean those points? Would I be safe as long as I put the magneto back the exact same way? I am not too familiar with the spacing of .013 for the magneto. How would I determine if that is correct when I take the magneto apart? The magneto is an F4.

Thank you for the feedback. I am new to working on a magneto so I have a couple of questions. What part of the magneto is the advance cover? When I take the advance cover off can I pull the points out right away and put them back in? Or does it require a little work to remove the points or level them and wipe them down? What should I clean the points with?

Thanks for the feedback! Yes, I do know where the shut off lever is up by the steering wheel. The sweet spot for starting it is about 1/2 way down. How do you recommend getting to the points and what should I use to clean them?

Thank you for the feedback! When I crank the tractor it did have resistance when I would pull up on the crank. How would I verify that there is a stuck valve? Would it the tractor never attempt to turn over if there is a stuck valve? I am still in the learning process of how all this stuff works.

Thank you I appreciate it! I have been putting the lever 1/2 way down and it originally was always starting for me. I have been told time and time again to never wrap your finger or spring the crank around and around so I do not do that. LOL - Next time I am out there I will pull start it to see what is going on. If I pull start the tractor should I have the advance all the way down as if the tractor is already running?
Thank you again!

(quoted from post at 11:58:59 08/25/20) Thank you. How would I take the magneto apart to clean those points? Would I be safe as long as I put the magneto back the exact same way? I am not too familiar with the spacing of .013 for the magneto. How would I determine if that is correct when I take the magneto apart? The magneto is an F4.

Click to expand...

First of all, you would not take the magneto all the way off. You would just remove the cap. I've not worked with too many IH magnetos, but on most mags the points would be visible when you take the cap off. I use real fine emery cloth; others would say just a piece of of card stock or something similar. Running it between the points several times should remove any corrosion and shine them up good.
To check the gap you would need a feeler gauge of that thickness. Turn the engine over till the points are open, then use your gauge to see what you have. But before doing that, I would just clean them up first and try that. If it starts then, don't worry about the gap--it's probably OK.

It's safe to turn it all the way around with the plug wires off, it can't kick back with no ignition source.

You're feeling for compression on all four cylinders, all should feel the same, should be a compression stroke on each complete revolution.

A stuck valve will show as one turn with no compression resistance.

It will still turn over and run with a stuck valve, just run poorly, shake, loss of power.

Good to know, thank you!