Hey guys, thought I'd reach out for some help on my starting issue and get your $.02.
Background: K301 on a 1964 model 70, Complete rebuild 3 years ago and I used most of Brian Millers tricks for stock puller: offset reground crank pin, shaved head, BM pulling cam, 30mm carb, mild porting work on exhaust.
The engine ran awesome since rebuild up until approx last fall. Typical Kohler quick starting (hot or cold), lots of power, no issues at all and I was very happy with the engine. Then last summer it started getting "slower" to start and got progressively worse. Typically it would just backfire with a loud bang and require lots of cranking. Starting fluid didn't seem to make any difference either. Tractor would pull start easily and once started, it would run like nothing was wrong. Nice and smooth, good throttle response, etc.
I did a bunch of research on this site and did the following: Rebuilt starter/generator, carb kit, changed points, spark plug, colder spark plug, condensor, and maybe a few others?
No improvement. Zip, Zero, Nada! It was like I didn't do anything?
I then used a meter to static time the engine. The static timing showed that timing was delayed and when I opened the gap slightly (.021") to advance it to the proper spot, it actually made it worse (heavy backfiring during attempts to start). I then delayed the timing (.017" gap) and I could get it to start on it's own again, but still lots of cranking and an occasional backfire. Oh yeah, the spark is nice and fat across the plug.
At this point, I'm ready to put a stock head back on, stock carb and stock cam. I'm reluctant because the engine ran so well before slowly deteriorating over the last year, but this thing was so overpowered that I don't care about the HP drop. I just want it to run and be a daily driver.
Thoughts?
