1945 John Deere B Hand Start

[johndeere48]

I have four hand start john deere B's that I totally restored, They all start pretty easy by hand. I recently completely restore a 1945 john deere B hand start. I can not get it started by hand. If I pull it, it starts within 20 feet. Starts right up real easy. What am I doing wrong with this tractor?

 

[Paul_IN]

Maybe the magneto impulse spring is weak?

Have you tried swapping parts from your other tractors to help isolate if spark or fuel mixture?

 

[MSD]

Try adjusting the impulse degree on the back of the mag.

 

[johndeere48]

Try adjusting the impulse degree on the back of the mag.

Where is the impulse degree on the mag?
I do have good spark and a good sounding snap when the mag trips.
Also this is a brand new (rebuilt) mag.

 

[Fixingfarmer]

Where is the impulse degree on the mag?
I do have good spark and a good sounding snap when the mag trips.
Also this is a brand new (rebuilt) mag.

So likely not spark. Starts and runs well when pulled….

Could be low on fuel (does it backfire? Strangely enough you would think that’s a rich condition but 2 cylinders backfire amazingly well when lean) it doesn’t happen to have a new carb as well to go with the fresh mag? Some of the ones sold nearby take an extra turn out on the idle screw because the threads are different.

(Here’s what I think it is if you haven’t purchased a new carb) check for an air leak around intake manifold. Condition of the manifold itself. Carb gasket if you remove the carb put a new gasket in. Keep them fresh on the intake side.

Other things,

Possibly low on compression?

Checking compression and timing you should be able to hear the mag trip when you spin them by hand slowly. If it runs and the mags new it’s likely timed ok.

The suggestion of swapping mags is still a good one if everything intake wise and compression checks out swap with a known running tractor this would confirm a mag issue. Twins can solve some of the worst things to diagnose.

 

[johndeere48]

So likely not spark. Starts and runs well when pulled….

Could be low on fuel (does it backfire? Strangely enough you would think that’s a rich condition but 2 cylinders backfire amazingly well when lean) it doesn’t happen to have a new carb as well to go with the fresh mag? Some of the ones sold nearby take an extra turn out on the idle screw because the threads are different.

(Here’s what I think it is if you haven’t purchased a new carb) check for an air leak around intake manifold. Condition of the manifold itself. Carb gasket if you remove the carb put a new gasket in. Keep them fresh on the intake side.

Other things,

Possibly low on compression?

Checking compression and timing you should be able to hear the mag trip when you spin them by hand slowly. If it runs and the mags new it’s likely timed ok.

The suggestion of swapping mags is still a good one if everything intake wise and compression checks out swap with a known running tractor this would confirm a mag issue. Twins can solve some of the worst things to diagnose.

Thanks for responing,
The tractor has a rebuilt carb, rebuilt mag, doesn't backfire, new valves, new rings, and I'm pretty sure the timing is set correctly. I'll look into some of your other suggestions. thanks

 

[MSD]

Where is the impulse degree on the mag?
I do have good spark and a good sounding snap when the mag trips.
Also this is a brand new (rebuilt) mag.

Here is a video that explains how set it up properly. Hope it helps you.

 

[a49deere]

I'm thinking timing is off, what was your procedure for checking that? low compression, valves not timed correct, to cold of spark plugs, flooding when turning over by hand!

 

[old]

I have four hand start john deere B's that I totally restored, They all start pretty easy by hand. I recently completely restore a 1945 john deere B hand start. I can not get it started by hand. If I pull it, it starts within 20 feet. Starts right up real easy. What am I doing wrong with this tractor?

My 1935 JD B is hard to start the first time each year but if I pull it one time it starts easy and then after that is starts pretty easy by hand. Or at least that is how it was the last time I started it. Haven't needed it so it hasn't been started in a long while

 

[miangus]

I had one once with a bad weak impulse catch on the mag. If you just palmed it over slowly the lock would catch and it would start. If you tried to pull it over the catch would not lock. Towing it spins the mag fast enough to generate a spark.