Why does this help our Waverunner?

Joined
May 29, 2005
Messages
860
Location
Ozark Mountains
An old 1995 Yamaha 1100 Waverunner we just bought was running badly. Would not get up to full power. Felt like a cylinder was not firing but they all were. We checked everything we could but it would not run any better. Finally my son tried turning the fuel select lever from full on to part off while running WOT and it started to run great. 62 mph by the spedo anyway. Why did this help???
 
Joined
Jan 10, 2008
Messages
4,998
Location
Milwaukee, WI
If it were a motorcycle, I'd say to get a rebuild kit for your petcock valve. On most, there are three holes in a rubber disc that can either shift or get full of crud. Also, some petcocks are vacuum actuated so they turn off when the engine is off. Perhaps there is a leak in this line, and closing the valve closes the path to the intake? Not sure. Anyway, I assume your problem is there. Are you sure you don't have a leak in the fuel line anywhere
 
Joined
Jul 9, 2008
Messages
715
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Ks
Is the knob rotated on the shaft a little? i.e. when it says its full on it really isn't.
 
Joined
Sep 5, 2008
Messages
4,627
Location
Western Washington
 Originally Posted By: ksJoe
Is the knob rotated on the shaft a little? i.e. when it says its full on it really isn't.
That's what I was thinking also. I had that happen to me on an old Suzuki MC.
 
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