K341 stalls during quick increase in throttle
 

Hi folks, apologies if the answer is readily available but after doing some google searching, I wasn’t able to find what I was looking for. . I have two issues. I have fully restored every aspect of my 1650. Governor is calibrated, new governor spring, new carb from isavetractors, new coil, condenser, points etc. everything is genuine Kohler except the carb. I just can’t get an original.

Anyway, after several adjustments I still can’t seem to get the transition from idle to high rpm to be smooth. Sometimes I get a stall out condition. I’m just curious if there’s an obvious adjustment I need to make to high speed adjustment to enrich or lean out. Is a lean or rich condition the general root cause here?

Second, even though the idle screw is correctly Allowing roughly 1400 rpm, when I reduce the throttle arm to its minimum setting, the idle still stays high and then gradually comes down several seconds later. In this condition the butterfly was checked to indeed be against the idle stop and governor atm was fully clockwise against stop. . This only happens when I run engine at high rpm for a period. Any ideas?

If you do not see black smoke and the transition is poor from idle to full throttle, it is probably lean. Experiment with the mixture screws. Once the engine is at operating temp, lightly seat then back them out 2 turns. Then fine tune them for the smoothest operation. If you are unable to get a good running engine, and the gasket from carb to engine is good, then the carb is at fault. Might have machining junk in the passages, or the float is out of whack.

Yup, I second that.

:IH Trusted Hand:

If it takes a while for the rpm's to drop and the butterfly is closed, check for vacuum leaks,as it has to be getting the air somewhere

Thanks guys. I’m worried the aftermarket carb is the issue and not my tuning skills.

Hey let me know how this turns out-- I am sort of in the same boat, and have the same carb. It had for 6 mos been running fine- but about a month ago started acting up. I tore the carb apart, cleaned it, but it was clean.