Misfire at full throttle K341
 

Hello, my Kohler K341 in my cub cadet 1650 will misfire at full throttle. It seems like it’s running rich because when it misfires it will belch Black smoke, but I have leaned the main jet back as far as I can so that it still runs at full throttle. Otherwise it runs at idle and mid throttle just fine and has good power. The misfire mostly occurs when I’m pushing snow or doing some heavy work. Any suggestions? Thank you in advance

Possibly a weak spark.
1. Check, clean, set your contact points,
2. Try a new condenser. (some guys run 2 condensers)
3. Try a new plug wire.
4. Try a new coil.

Could be your Carburetor is in need of cleaning, rebuilt, and/or adjusting.

:bigthink:

If you don't find any issues with the ignition or carburetor then possible weak valve springs. Had a 147 years ago that would idle perfect up to bout 1/4 throttle but 3/4 to full throttle it would backfire through the carb. Problem was the intake valve spring was very weak and would allow the valve to start floating and not closing tight at full throttle. New springs and lapped the valves and no more backfire

Thanks- the carb is new and very clean- I did check it recently. And it was running perfectly recently- but it may be ignition

Thanks- I will check all of these-