Missfire when not under load

[Kody Bob 17]

I have the c-145 running pretty good now but I noticed when I have the clutch disconnected the engine seems to missfire. This happens at idle or WOT. As soon as the clutch is engaged the miss stops. Any ideas what would cause this?

[oliver2-44 10,734]

When my C-160 K341 was new to me, it would backfire mostly at WOT but a little at idle. I went through the carb more than once with no change and adjusting the carb screws really didn't cause much engine response. I had also verified the timing was correct.  I cleaned some oxidation off the points by pulling some brown paper bag paper through them several times, and it helped a little.  I read that a bad condenser could cause this backfire at WOT so I replaced mine.  What a difference it made.  I was then able to tune/lean the carb main jet and it ran great. 

 

So while I try not to just throw replacement parts at problems, a condenser is an inexpensive part to try replacing.

[squonk 43,843]

Try closing the choke a tad to see if the miss goes away for the heck of it. My Power King with a K321 would hesitate and sputter when letting out the clutch. New points and condenser cured that problem

[953 nut 60,083]

19 hours ago, Kody Bob said:

engine seems to missfire.

                                        

If your's is like most small engines the ignition system hasn't been properly serviced in a few decades. A new set of ignition points and condenser (Kohler, not the cheap ones) a new spark plug and setting the ignition timing will make a world of difference.

Kohler static_timing.pdf

Once that is done you can fine tune the carburetor.