25 HP Yamaha stalls at wide open throttle

[kona-jack]

Hello <br />I have a 25 hp fourstroke Yamaha that stalls out when running at high rpm. This is a 2000 F25ELHY. Two pistons with a single carburator. This motor will run fine in the driveway but when I run it in the water it will run for a while then stall. It will restart after waiting a few minutes. I have rebuilt the carb which eliminated a low idle problem. I checked the fuel pressure and it read about 5 psi when cranking the motor. I have changed the fuel filter also. I have also drained the fuel tank to make sure there was'nt any water in the fuel. The primer bulb does appear to work. I think its fuel restriction problem. Any suggestions.<br /><br />Tim in Georgia<br /> <br /> <br /><br /> torr@csam.net

 

[RandyJ]

Re: 25 HP Yamaha stalls at wide open throttle

Sounds much like problems I've had all summer with several boats and pwc's. If you have free flowing fuel at the end of the fuel line to the carbureator then you may have a base gasket leaking, pulse line to fuel pump sucking air, or even a stuck float valve... somewhere in the fuel system you appear to have a problem...even a kink in the fuel line can cause this. I have two right now that run great at WOT as long as I give it about 1/2 choke...still can't find the restriction or where it is getting too much air...one or the other I've got the problem narrowed down that far.

 

[kona-jack]

Re: 25 HP Yamaha stalls at wide open throttle

Thanks I'll check it out.