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Merc 115 hp 2004 too much fuel/ engine misfire.

Sambuka101@aol.com

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Driving me crazy! Spark plugs are black with fuel. Changed thermal switch, and new coils . VST seems to be problem, however my mobile tech says fuel regulator could be bad. After paying him a thousand bucks,to replace the spark distributor, t-stat, timing belt. I still have a major mis-fire . Too much fuel! This is 4 stroke, EFI motor, built by Yamaha, painted by Mercury. Any help!!!

Thanks for any ideas. And running out of patience and CASH!!
 
Found the problem, yea!!!! The high pressure pump in the vst unit, the grommet that holds the pump in place was out of place ( down around the pump). The grommet was so swollen it forced its way out. Alowing the fuel to free flow into the vst bowl. Over flow runs free into intake manifold. No more fuel injector cleaner for me. Used Lucas injector cleaner. Don't do it on any older motor.
 
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