Deisels for over 20 secs when shut off and won't restart.

My Briggs and stratton 21 hp OHV engine diesels after mowing and shutting it off and then it won't restart sounding like a dead battery. Have tried new starter and coil and battery.

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It never did restart? It does this all the time? Give us more information?


It does restart if you let it sit for 1/2 hour or so. It sometimes backfires too, both when shutting down and starting but not very often on either. I read the Briggs and Stratton website that says if you have a fuel shut off solenoid, you should shut down the mower at full throttle. I'm going to try that. At least it won't cost me anything.


this could also be an overheating issue . its air cooled and if the cooling vanes get filled with grass clippings and dirt it does not cool properly . try removing the engine cover and blowing out the vanes


Not a problem as they are so clean they look new.


Replaced the spark plugs today. They had a thick powdery carbon coating. Is this the type of carbon that can create dieseling? Of course thAt would not explain the won't restart issue. Is that a vapor lock or compresssion issue?


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You don't have to fully throttle it up just halfway will work most times. Also check the plug for carbon deposits that will build up heat and cause ignition.

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