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DMKNLD

K321 troubleshooting help needed

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DMKNLD

My 7114 Kohler 321 has had a miss under load that neither I nor my local small engine guy can seem to figure out. The 'make a short story long' history on this - a fresh engine rebuild last fall w/ no probs snowblowing at full throttle over the winter, then it starts to intermittently run rough and miss this spring. After tweaking w/ the carb adjustments it stalls out and does a monster backfire and blows a 1/2" hole out of the side of the cylinder head, which I replace w/ a used one in good shape w/ a new HG.

Still can't get it timed right, so I take it back to the shop and he finds a warn cam shaft pin that secures it to the engine block. He pulls the engine and fabricates a new pin to hold the cam in place. Then it will idle smooth and throttle up fine, but still has an intermittent engine miss when the belly mower load is put on it mowing high grass.

New parts include a Walbro carb rebuild, new NAPA coil and condenser, new kohler points, valves readjusted, governor adjusted, new spark plug and air filter, new fuel filter, cleaned the fuel pump and diaphragm, loosened the gas cap to rule out a faulty cap vent, flushed the old gas and added some Seafoam for ethanol fuel treatment. Tried jumping the battery direct to the coil to bypass the rest of the electrical system and still no difference. Any suggestions on what else it might be?

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RickS

I am not an expert by any stretch, but have you checked the key that holds the flywheel on? If it is broken or partially sheared it will affect the timing.

Rick........

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powerking_one

Dennis,

The cast iron Kohlers are not known/notorious for any flywheel key (steel) shearing issues. If you have a timing light, connect it and monitor the "S" mark on the flywheel through the inspection hole to see if the ignition is dropping out when this mis-fire event occurs. Perhaps the points primary wire to the "-" side of the coil has a isulation breach and is shorting out causing an intermittent ignition dropout problem?

My 2 cents worth of thoughts....:J

Tom (PK)

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Brettw

I do not believe a K321 is timed by the flywheel. It has points, a points plunger that runs off of the camshaft, and a battery powered coil to provide spark.

That coil, may, under load, get hot and begin to act up. That could be an issue amongst others. A new coil should be available at NAPA if that is the problem.

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powerking_one

Dennis already stated that the 12V coil was replaced and yes, Kohler C.I. singles get their ignition timing from the points plunger off the camshaft. Rarely do the Delco 12V coils fail. The possible last thing suggested to check was the wire from the points to the coil.

Tom (PK)

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