Kohler K321s BACKFIRES then quits.

[daveoman1966 3,815]

My Bronco 14 has the original Kohler K321s with electronic ignition. I recently 'rebuilt' the carburetor and swapped in a known good fuel pump.  Also have replaced the fuel lines and installed new fuel filter.  PROBLEM: When mowing today, the engine backfired and stalled out 3 times...blowing black smoke while it was shutting down.  I was able to restart each time to finish mowing, but the black smoke continues for a few seconds when the engine gets up to rev.     

What gives?  

[Goldnboy 1,006]

Last time that kind of issue with back fire was when I got close to a tree and it bent hood and it touched the condenser causing a short...but your on solid state ignition 

[tunahead72 2,518]

@daveoman1966 You might find some ideas here:

 

312-8 backfires , chokes - Engines - RedSquare Wheel Horse Forum

 

[siebenaler 114]

Why did you rebuild the carburetor was it giving you issues.  Is it the original carburetor. 

Does it run fine at idle.

Does it only happen on a high speed after engine is well warmed up.

[ebinmaine 70,810]

Has the head been pulled and engine decarboned? 

 

Valves checked for condition and properly adjusted? 

 

Is the muffler in good solid condition? 

 

[gwest_ca-(File Mod) 11,253]

I've always blamed the spark plug because after replacement good to go.

[953 nut 58,024]

Here are some things to look at.

# 1           Spark plug

#2            Spark plug wire

#3            Wire from trigger module to coil