John Deere M

[Tim14167]

I have a 1951 John Deere M and it is hard to start. Well, it starts and runs great, but it just does not turn over the way it should. When it gets to a compression stroke it basiclly dies out. Then once it gets past the compression stoke and onto the exhuast stoke it usually gets a enough momentem to spin fast enough and start. Then sometime it will spin over perfectly fine.

This is usually a sure sign of a weak battery or a connection problem. This is what I have done, If I have missed something please let me know!
New Battery, new battery cables (2/0 copper), I took the Positive lead and attached it to the set screw and jam nut that holds the starter in the torque tube becuase I figured after 60 years of use it was not making a good connection between the torque tube and the insterment panel, ground all the conncetion surfaces to ensure connectivity, rebuilt the starter, new starter switch, new starter stud...what am I mising here? Thanks in advance

 

[teddy52food]

Load test the battery.

 

[JD John]

Maybe the timing? Just a thought, I know if its off a little it will do what you are describing.

 

[Dave H]

Tim, I have a 420 exactly like that and basically have done what you have done.

The next thing was going to be the starter for me but what the hey, I get it started.

 

[Tim14167]

literally a brand new battery. The original battery was 625 CCA. I made a new battery box and put in a high performance 6 volt battery, 800 CCA...Still same issue, but it does spin faster when it gets past the compression stroke.

 

[teddy52food]

Just because it is new, doesn't mean it is good. What is the voltage drop when coming up on compression?

 

[RLA]

I too have a 49 M, went threw the whole tractor
& once in a while on the compression stroke it
will come to about a complete stop while
cranking engine. The starter is fine, the
compression very good & load test on Battery
is what it should be. I think it depends on
where the engine stops. It starts fine everytime
but once it a while I think the battery is dead.
Since it always starts, I am not going to try
& fix it anymore....

 

[shadetreegarage]

I have an MI that does that too, but my M and MT don"t act that way. Let us know if you find out the cause. Thanks.

 

[Hayfarmer]

Glad to know it isn't just me. I have an early 320 that starts like that. New battery, super heavy cables. I usually think it isn't going to start, but then rolls again and takes off. My MT spins over good and does not have as heavy of cables. My 430 used to do the same thing until I converted it to 12 volt.

 

[Mike M]

If I remember right ? There was a HD starter available with 4 full field coils. This is what you want.

 

[M-MAN]

Timing could cause it. A sticking distributer advance can cause the timing issue even if it checks fine with a light. Then there is the possibility of a leaky needle and seat letting a little fuel build in the carb. Pull the starter and it sucks it into the cylinder. A small amount will almost stop it from turning over & a larger amount will stop it. Got all those t shirts over the years.