1949 Styled Model A hot start issue

Hi all -

I'm new to this forum so I apologize in advance for any "discussion board faux pas" I might commit.

I am in the process of restoring my Dad's 1949 Model A John Deere and even though I'm only at the point replacing a rear wheel bearing and have not started to do engine work... there is something that i remember about the tractor that was a problem and I wanted to see if anyone else has had seen the same issue.

The problem was this - it is electric start - and when it was cold, it always started right up. But after it was run for a while and got warm/hot it would not start. My uncle tells me that my Dad was pretty good at setting the throttle just right and get it to start hot sometimes... but my uncle could never get that to work for him.

I have an old Yamaha golf cart that had the same symptoms - and I realize that there is a WORLD of difference between a mid-1970's Yamaha 2 cycle engine and a 1949 Model A engine... but with the Yamaha engine, when it got hot the block would expand and basically ruin the compression enough to make it so that it would not start. I had it rebuilt and re-bored and it works like a charm now. I'm sure that the tolerances are not nearly that tight on the Model A, but could the problem be similar? Compression loss?

My Brother in law guessed it would be more of an issue with the magneto or ignition system - but I don't know how heat would affect that.

Any ideas?

Scott

Scott, I am by no means an expert but what I do know is that heat does have an effect on the coil in a magneto, it could be caused by too wide of a point gap, too wide of a spark plug gap or just the fact that the coil is probably 60+ years old.

It could be as simple as replacing the points and condenser, I recently had a problem with my 52 A dying after it got warm, I still had current coming from the coil which led me to the condenser being bad. I replaced he points and condenser in the distributor and have not had that problem since.

I agree with the coil problem

i agree with weme and rick: we chased a warm/hot stalling problem on our 70 until we figured out it was the condenser, but in my experience, both coil and condenser heat issues usually cause stalling not just restarting issues. One thing I can attest to learning the hard way on Deeres is "think carb and when ya dont think its the carb, think harder that its the carb!" Esp with ethanol gas. Also have you checked your valve tappet clearances in years?
One other suggestion: we had a 620 that would start and run fine but wouldnt restart hot, it was the manifold gasket which you would think would get better when warm but who knows sometimes!

Thanks so much guys!

That's given me some really great places to start looking. For the most part, all of those suggestions are probably less expensive and troubling to deal with than compression! I'll start with the points and condenser and then move on to the carb. I suspect that I'll be rebuilding the carb anyhow - so that's just as well.

Thanks again!

Scott

(quoted from post at 15:31:34 05/11/15) Thanks so much guys!

That's given me some really great places to start looking. For the most part, all of those suggestions are probably less expensive and troubling to deal with than compression! I'll start with the points and condenser and then move on to the carb. I suspect that I'll be rebuilding the carb anyhow - so that's just as well.

Thanks again!

Scott

Click to expand...

A word of advise to you if you plan to overhaul the carb yourself, make sure you clean the secret passages and the nozzle in the carb, make sure your throttle shaft bushing is in good condition as well as the throttle plate. In my own experience I have found that a good quality overhaul kit, new throttle shaft bushing and plate are well worth the extra money ($15 more maybe) invested compared to fighting an idle or surging issue and having to remove the carb and replace those parts in the end.

Strange, but my '52 "B" must be choked to re-start, if I kill it Hot...!!! Yea, it smokes when it starts, but it Starts...other-wise it just keeps cranking...

NO 2 of them seem to be alike..!!

Ron..

For quality carb rebuild , cleaning all the so called secret passages, Motec engineering Tipton Ind. Best i EVER FOUND AND GUY YOU CAN WORK WITH.