1950 JD A starting issues

[Huston 1950 A]

The tractor starts very easy with a pull start. However, when using the starter , the engine spins rapidly but does not fire.
When the starter is released, the engine will fire through momentum, we'll get 1 or 2 pops ans if lucky it starts.
The ground from battery to frame is good.
Hopefully this group can help us out.
Thanks

 

[teddy52food]

Magneto or battery ign.?

 

[Huston 1950 A]

Magneto ignition on 1950 JD A

 

[Pappy]

My Farmall 200 would do the same thing. Would not start with starter, but would start easily with the hand crank. Now, this does not relate to
a magneto. The coil was bad.

 

[teddy52food]

Sounds like the impulse is not catching at cranking speed, but catches as it slows down. I work on them as a hobby. Let me know if you need help.

 

[Huston 1950 A]

Sounds like the impulse is not catching at cranking speed, but catches as it slows down. I work on them as a hobby. Let me know if you need help.

Thanks for the input, how is the impulse checked

 

[bob p mn]

When I would have troubles with Mag's I took the easy way out and installed a Delco distributor in it's place. Didn't have a Mag rebuilder around here, I would pick up a Delco at the swap meets and always had a spare on hand.

 

[Huston 1950 A]

Yesterday my son entered a pull and the tractor was misfiring, could this be related to the starting issues, we were using new spark plugs.

 

[teddy52food]

Thanks for the input, how is the impulse checked

If you can turn it over by hand you should hear a loud snap or click. Not a dull thud. The pins were the dogs are on get loose in the plate & don't catch & hold the way they should. I stake them & spot weld to keep them from coming loose again.

 

[teddy52food]

View attachment 78932
Yesterday my son entered a pull and the tractor was misfiring, could this be related to the starting issues, we were using new spark plugs.

Sounds like the whole mag needs to be checked out. I have the testers and a magnet charger to get them up to snuff again. Let me know. I usually get 30/ 35 for labor plus parts.

 

[Huston 1950 A]

Sounds like the whole mag needs to be checked out. I have the testers and a magnet charger to get them up to snuff again. Let me know. I usually get 30/ 35 for labor plus parts.

Where are you, we're in Ontario

 

[John T]

Without going into the weeds I agree with Teddys good advice. Often if a mag tractor starts fine pull started but not cranked the issue may be mag related. As my friend Dan pointed out and we agree other causes could be carb related due to a vacuum leak such as worn throttle shaft bushings in the carb or other vacuum leaks. Also start timing is critical the mag needs to trip impulse and fire right at tdc

John T

 

[MSD]

I had a 29 D one time. You could crank your butt off and it not go. Pull it 3 feet and it would start. Always figured it was the mag but sold it before I got it fixed.

 

[MSD]

View attachment 78932
Yesterday my son entered a pull and the tractor was misfiring, could this be related to the starting issues, we were using new spark plugs.

How wide do you have the plugs gapped? Those JD's don't like a wide gap. We run all our's at 16-18 thousands.

 

[teddy52food]

Where are you, we're in Ontario

Freeport which is in central Mn.