[Rhodes22-list] Another ethanol-related failure point

[david.walker5 at comcast.net]

I too am having OB problems with my Yamaha 9.9. Will not idle and speed hunts up and down. Prelim diagnosis is a clogged idle jet. I don't understand why small OB's are so finicky. I have a Honda snow blower that is 15 years old never been worked on never had gas additive never had the gas run out at the end of the season and has always stored outside  and has never failed to start on the first pull and run perfectly.  

Dave
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: John Lock <jlock at relevantarts.com>

Date: Thu, 13 Aug 2009 15:27:32 
To: Rhodes 22<rhodes22-list at rhodes22.org>
Subject: [Rhodes22-list] Another ethanol-related failure point


About 2 weekends ago my trusty Nissan 8hp outboard quit while we were  
motoring home under windless skies.  Fortunately not too far from home  
and we got a tow in.

Fiddled with it a while and could get it to run for 15-30 seconds or  
so and then it would just die.  Checked tank vent, filter, fuel line  
and confirmed that fuel was flowing freely all the way up to the  
carburetor.

Having a little experience with outboard repair, I took the carburetor  
off and dismantled it.  On closer inspection I realized the float  
valve was sticking up - in the closed position.  So, it would let fuel  
into the carburetor until it closed and then never opened again.  The  
engine would use up what was in the float bowl and quit.  A couple  
raps on the side with a screwdriver would sometimes knock it loose and  
let fuel come in again.

So... the problem was obvious but the cause was more insidious.  The  
float valve (also called the needle valve) has a rubber tip that seals  
the fuel inlet opening when the float rises and the carb bowl is  
full.  But ethanol had degraded the rubber tip, making it soft and  
sticky.  The float would push it up in the valve chamber and the  
rubber would deform and stick in the narrow opening.  So, no more fuel  
coming in until it got knocked loose again.

Strangely, the other rubber parts seemed to be in good condition.  But  
I ordered a carb kit and replaced everything anyway.  Now tt's back to  
its usual smooth running self.

Another thing to check if you have fuel-related problems...

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

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