Stops at full throttle-Yamaha

[msfishing]

Starts and idles ok, but put in gear and run for a few seconds it comes to a stop, until you pump bulb. Then its ok for a few more seconds and stops again. Have cleaned carbs, replaced spark plugs and checked fuel filter. Also put a bottle of something to take water out of gas in boat fuel tank and replaced bulb on fuel line. Seems fine when we are running at home, but problem occurs when you put it in the water.

 

[JB]

Re: Stops at full throttle-Yamaha

Howdy, MS Fishing. Welcome to the board.<br /><br />You need to tell us everything when you post a problem. What is the year and model of your Yammy? Is it 2 stroke or 4 stroke?<br /><br />You almost certainly have a weak fuel pump or, if your engine has only one carb, a gummed up carb.<br /><br />Overhaul your fuel pump and you should be okay.<br /><br />Red sky at night. . .<br />JB

 

[pthein]

Re: Stops at full throttle-Yamaha

before you go to the trouble of rebuilding the carb, I found from experience that the fitting where the fuel hose attaches to the motor can cause a fuel/air leak. When you pump the fuel bulb it gets hard, but if you hold it squeezed does it slowly leak down? If so I would bet you have a fuel leak somewhere that under load causes a air leak. At idle there is not enough suction to pull in air. I found my leak but doing this proceedure and found a small fuel leak. Amazing that something so small and so easy to fix can cause so much trouble. Let me know if this is the problem....

 

[msfishing]

Re: Stops at full throttle-Yamaha

Replaced fuel line on 1987 2 carb Yamaha and stays running a lot better, but did lose pressure again today. Had to pump bulb and it was ok for a while then lost it again. Then all of a sudden it was ok for the rest of day.