Fuel pump location on a 1998 yamaha wave runner xlt 760

First, empty your fuel tank and pour a 2% fuel mix in it.
Remove the oil hoses coming to the carbs. Put the ends in 2 recipients.
Run the engine for a few minutes. Oil must come in the recipients. I couldn't find an exact quantity in the Service manuals.
The theoretical mix is 50:1 ( 50 liters fuel with 1 liter oil)
So, the best way is to have a full tank 50/1 fuel/oil mixture AND a full oil tank.
Sail a few hours, refuel ( count how many liter you've burned. Refill the oil tank to level.
Check that the fuel/oil ratio is about 50:1.
You can adjust the mixture with the cable on the oil pump.

it is possible that it is a carby problem or pump diaphragm
the problem indicates insufficient fuel when under load from the pump ( not under load when out of the water)

does it have spark at plugs ? carb clean and fuel new ?

Fuel pump or filter my be blocked fuel line.

find where throttle cable attatches to carbs and on that wheel there is a lip on the inside and a screw should be there that you adjust the tickover !! P...

An engine that dies under load but starts ok and idles ok has a fuel blockage in the main jet . Possible from water in the fuel in the carby. Water will not pass through the jet and blocks up the hole A trick that is used is to place a pint of metholated spirits in with the fuel. It breaks down the surface tension of the water and allows it to pass through the jet.

Sounds like the carbs are gummed up from the old gas sitting in them. Remove the carbs, disassemble, clean with a carb cleaner, and reassemble.

There is no adjustment on the oil pump it is a steady direct drive/flow system. If the oil pump is not working correctly you have two options. One is to replace it for around $400. The other is to remove the pump, cover the opening with an aluminum plate, and pre-mix your oil and gas at a 50:1 mixture.

http://www.boats.net/parts/search/Yamaha/Waverunner/1991/WR650P%20WaveRunner%20LX/JET%20UNIT/parts.html. I hope this link helps, this should tell you all you need to know. Thanks for using fixya, mike

Have you tried to richen up the low speed on the carb?