[Rhodes22-list] a Yamaha mechanic in the house?

[John Lock]

On Apr 28, 2009, at 09:47, Joe Babb wrote:
> My 1998 Yamaha 9.9hp outboard has taken a dislike to running much  
> above
> idle.  It starts up fine.  Runs mostly okay at idle and slightly above
> idle, but stalls and quits when I try to advance the throttle.  I  
> pulled
> the spark plugs and they are dark and a little wet.

I doubt it's the plugs.  If they are wet, then I suspect you're not  
getting enough air into the cylinder (or too much fuel) as the engine  
revs.  Maybe clogged air filter or choke is stuck closed.  Another  
thing to check is the needle valve in the carburetor bowl.  It's  
supposed to shut off fuel flow when full, but a tiny piece of crud can  
block it open and fuel continues to pump into the intakes.  This is a  
common failure when alcohol-enhanced fuel degrades rubber fuel lines  
and there is no fuel filter at the carb.  Another failure I've seen  
(in cars) is that the float in the fuel bowl develops a leak and no  
longer floats, so again the needle valve doesn't shut off fuel flow  
when it's supposed to.


Cheers!
John Lock
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s/v Pandion - '79 Rhodes 22
Lake Sinclair, GA
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