Question about 2003 Yamaha WR 250 F

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2003 WR250 F - eng. won't idle down and carb starts to overflow

When the bike really warms up running dirt roads, the engine starts to rev higher and won't idle down on its own - eventually, the carb starts to overflow. After shutting down for a while, the carb overflows when I just turn the petcock on. Carb's been cleaned, needle replaced, rubber diaphram (?) replaced, etc. Still a problem.

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  • jwelden Mar 09, 2009

    Also turned out that there was algae kind of material in the very bottom corners of the gas tank and the petcock was also gummed up and needed to be replaced. I guess the guy that had it before I got it let it sit for too long with gas in it. Runs great now!

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  • Yamaha Master
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Hi Jwelden,
Have you checked the float level in the float chamber?
I guess you may have to reset the float pin adjustment, its allowing more gas to pass through thn required and thus the overflow!
Not bad too, when you are working on the float assembly take the opportunity to blow out the fuel line from petcock to the carburator via the seat for the float pin,any foreign particals there would stop the float pin to seal up and thus overflow.
Fit in an inline fuel filter , this will help keep out the dirt or whatever.
Hope this helps.

Knight (Yamaha Seca XJ750A 1981)


Posted on Feb 13, 2009

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