John Deere 60v backfire problem

[japfpe]

My late 70's vintage JD 60V just started backfiring recently when under heavy load. The backfire seems to be coming thru the exhaust. First opinion is that the point setting (clearance) is probably off. Any ideas ? Also anyone one know the proper point gap for the saw ?

Thanks,
Joe
Fayetteville, NY

 

[Crofter]

I would suspect lean mixture causing hot running and exhaust. Is carb setting still correct or has this changed too. Eliminate any possible air leak before you run it this way.

Frank