25 hp 2004 Yamaha 4 stroke problems

[tomgarter]

I have a 2004 25hp four stroke that stalls on acceleration. The motor Idles and starts easily but won't run any faster than idle speed. I've replaced the fuel pump, fuel lines, tank and pumping the ball does not help. My local Yamaha dealer said it sounds like it electical so I replaced the plugs. It didn't help. Where should I look next?

[boscoe99]

What is the complete model identity?

Does your model have an accelerator pump? If so, gasoline gets sprayed into the carburetor inlet whenever the throttle is quickly advanced. Through a very tiny hole on the downstream side of a small brass tube that runs horizontally across the inlet of the carburetor. Can you see gasoline coming out of the tube?

Possible the accelerator pump nozzle is clogged.

But even if the nozzle is clogged you should be able to get the motor to run at high speed by ever so slowly advancing the throttle.

When was the last time the carburetor was completely dismantled and thoroughly cleaned in a heated ultrasonic cleaner?

[tomgarter]

yamaha 25hp F25TLRC

I just ordered gaskets and jets for a carb clean and rebuild. Are you cofident the problem is crap in the carb?

[99yam40]

not sure how positive he can be without him seeing and testing, but fuel problems are usually the most prevalent

[boscoe99]

I am never absolutely positively sure of anything.