1997 Yamaha GP760 fuel problems....

[Crystal760]

Hello everyone, I have a 97 GP760 and I am getting no fuel to the carbs. From what info I have gathered so far, the "pump" is a diaphragm built onto each carb....there is no fuel spraying into the carbs however, I can take the fuel filter off, turn it upside down so that the fuel runs down the line towards the carbs and it will start right up until the fuel burns out. Whenever you replace the fuel filter it in turn fills up with gasoline again. This could possibly be the cause of a bad diaphram, but also, I have read if the diaphram is bad fuel will leak out. Would I be able to see the fuel leaking into the carbs? I don't see anything....just wondering if there is anything else it could be? All help is appreciated!

 

[rogerwa]

Re: 1997 Yamaha GP760 fuel problems....

Is this a new problem? How long have you had the unit and when did this start?

While the most likely culprit seems to be the carbs, and working through those would not be a waste of time, you are also reliant on free flow from the tank, though the filter and then the return trip to the tank. Is your vent tube working properly and did you relive pressure by openning the cap?? That is the supply side.

Your fuel pumps also rely on the pulse from the crankcase to supply the pressure change that pumps the fuel. If you have compression and a sealed case this is a fairly simple process, but the pulse is required to pump fuel. Check the pulse hoses to ensure they are not kinked, collapsed, or not attached.

 

[tankengine]

Re: 1997 Yamaha GP760 fuel problems....

I had a similar issue a month ago after my wife started our waverunner with the fuel selector on "off". It started, ran for about 30 sec and died...then I couldn't get it started for a couple days. I was talking to a friend about it and he told me to stand on the right side of the ski, hold the choke out (hold it hard), reach across and hit the starter and at the same time lean your chin on the throttle just a bit (or a 3rd hand it you have one).....sounds stupid, but I did just that, leaned on the started for about 10-12 secs and it fired right up. He told that Yamaha's sometimes get airlocked....not sure how true that is, but I got it started. Since then my borther-in-law did that same thing my wife did....I had the same issue and the chin method got it fixed again.

I had tried everything else you've done..I pullled the fuel filter, checked the pullse lines, relieved the pressure by venting the cap, checked for fuel getting to the carbs....none of it worked until I tried this and it worked.

hope it helps