150hp Yamaha with no power

[billmc]

My 2001 Yamaha 150 V6 started missing and lost power. I replaced the fuel filter and the spark plugs. It misses and will only reach about 3500 rpm. Any suggestions regarding where to look next would be appreciated.<br /><br />By the way, anyone know where to get a service manual for the newer model Yamahas?

 

[jim dozier]

Re: 150hp Yamaha with no power

Is this a carbureted or EFI engine? Does pumping the fuel bulb help? If it is carbureted, does choking it help? You might check the tank venting system.

 

[billmc]

Re: 150hp Yamaha with no power

Thanks for responding jimd.<br /><br />It's the carb model. The fuel bulb is tight and there is fuel is in the filter bowl. I'll try choking it while running.<br /><br />I am assuming the vent is working since gas did come out the last time I filled up. I'll try it with the cap off.<br /><br />Thanks again.

 

[jim dozier]

Re: 150hp Yamaha with no power

You might also try to isolate which cylinder is misfiring by unplugging spark plug wires one at a time. If no change thats the bad cylinder. Then you need to isolate whether its ignition or fuel as the cause.