need help with farmall H with no spark

Sat Dec 29, 2012 12:05 pm

i am currently working on a Farmall H and we fixed the carb but now we seem to have no spark we checked the timing and we are getting power from the distributor i really wanna get it running for my boss. but im lost any ideas? :lost:

Re: need help with farmall H with no spark

Sat Dec 29, 2012 12:41 pm

Not exactly sure how to interpret "we are getting power from the distributor" along with "no spark". Tell us more about the checks you have run. Did you check for spark at the sparkplug end of a wire? What are you measuring when you say there is power at the distributor. Please confirm that you have a distributor and NOT a magneto, as the course of action might be different. If you truly have a "spark" at the distributor, then something between rotor, cap, wires, and plugs is causing it not to fire at the cylinder. If you are measuring coil voltage at the distributor, then along with all the possible culprits above, you need to add points and condenser. Tell us more about your trouble-shooting, and we can guide you to the cause more quickly.

Re: need help with farmall H with no spark

Sat Dec 29, 2012 1:11 pm

i beileve its a mag to be honest. i tested it with a continuity tester and as the result of that its getting power from the mag to the cap and rotor through the wires. but is it possible the plugs burnt out... im new to all this lol

Re: need help with farmall H with no spark

Thu Jan 03, 2013 2:29 pm

You wouldn't be able to test anything useful on a magneto with a continuity tester.

Odds of all four plugs getting "burnt out" simultaneously are zero. It's very uncommon for one plug to stop firing. That is easily checked by pulling the next plug and checking for spark there.

If two plugs aren't sparking, it's generally safe to say that you've got no spark at all. Normally your wires and plugs will be good enough to make the tractor run. Maybe not run well, but run.

Go out on google images and look up "farmall H distributor" and "farmall H magneto." Compare those photos to what you have to determine if you have a distributor (battery ignition) or a magneto.

The magneto generates its own electricity. It does not need power from the battery to make a spark. The only wire it has is for a kill switch. To ensure the kill switch is not your problem, unhook the wire from the magneto.

Distributors on the other hand require battery power to make a spark. To ensure you have power to the distributor, find where the wire connects to the ignition coil (the cylinder thing mounted to the top of the distributor) from the tractor's wiring harness. Turn on the ignition and then use a multimeter set on DC Volts measure voltage from that terminal to a spot anywhere on the tractor's frame. It should read around 6 Volts. If the meter has a needle that tries to go backwards when you do this, switch the probes.

The issue with a tractor that hasn't been started in a long time is usually corroded points under the distributor cap. Pull the cap off and clean the contact surfaces of the points with a points file, or a small metal fingernail file. Be careful not to mix up any wires (you shouldn't have to disconnect anything) and be careful to put everything back EXACTLY the way it came off. Both the magneto and distributor have points under their respective distributor caps.