2004 yamaha 4 stroke 150 hp

dbarker

Cadet
Joined
May 23, 2010
Messages
6
My engine has started smoking at idle and excess fuel is dumping out the exhaust. I removed the spark plugs after running at idle for a few minutes and #4 spark plug is wet with fuel. Engine seems to be running smooth maybe a little rougher than normal...

Any ideas what might be causing this problem?

Thanks
 

timster

Seaman Apprentice
Joined
May 22, 2010
Messages
37
Re: 2004 yamaha 4 stroke 150 hp

Have you checked for fire on the #4 spark plug??
 

dbarker

Cadet
Joined
May 23, 2010
Messages
6
Re: 2004 yamaha 4 stroke 150 hp

I have fire. I wonder if it could be the vapor recovery causing the excess fuel being released in the exhaust?
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 2004 yamaha 4 stroke 150 hp

most likly an injector leaking,a VST needle valve leaking or a bad pressure regulator.
vapor canister wont have anything to do with raw fuel in a cylinder.
 
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