Volvo Penta 43GL Run On or Dieseling

"I have had a 1999 volvo 4.3GL

"I have had a 1999 volvo 4.3GL for two years now. Last summer I noticed that the engine would continue to spuriously fire for a couple seconds after ignition shutoff, particularly after running at high speeds for more than 5-10 minutes. The only reason that I could think is that the engine is running too hot. I replaced the seawater impeller this spring, but am still having the same problem. I can feel water circulating through the hoses at idle speed. The boat's cluster temperature gauge indicates 180 deg when running hot, which I think is normal. The spark plugs are a nice grey/brown color. The carburator and flame arrestor are nice and clean. Any ideas??"

Craig: Have you checked the ti

Craig: Have you checked the timing lately? Does the motor seem to run OK @ Idle and good at top speeds?

"Some causes for the symptoms

"Some causes for the symptoms you are describing include: 1) carbon accumulated in pistons and/or heads, creating hot spots; 2) low octane gasoline; 3) spark plugs of the wrong heat range.

Have you tried to let the engine idle for a few minutes before turning the ignition key off? If you do this and the symptoms clear, then I would think hot spots are the cause; and if the don't, you may need gas of higher octane.

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