1993 Yamaha 115hp 2 stroke Fuel Starved

[fzamp1]

When I pump up the ball the engine will start but seems to "run out of gas" when the pressure is depleted. I have had tank cleaned, new pick up and fuel line to the new primer ball with integrated anti-siphon valve. Good pressure (when ball pumped) at the output of the fuel separater, inline fuel screen at motor is clean and just replaced the fuel pump. Same situation...starts but stalls when the pressure from the ball drops. If I continue to pump the ball, the engine will continue to run. Driving me crazy!! Help...

 

[99yam40]

Re: 1993 Yamaha 115hp 2 stroke Fuel Starved

sounds like the fuel pump is not functioning properly, hopefully you put a new gasket on where the fuel pump mounts to motor so that it can get the proper pulse from crank case.
A Fuel vacuum/pressure gauge will help troubleshoot the fuel system and a look at the frequently ask question part of the forum

 

[yamatech43]

Re: 1993 Yamaha 115hp 2 stroke Fuel Starved

You have the ball BEFORE the fuel/water separater? Between the fuel tank and the separater? This is WRONG....ball should be LAST thing before engine and PULL fuel thru separater....and the ball should point down slightly....also the serarater should be at least 1.5 ft. below the engine but ABOVE the fuel tank, not level with tank......it there another antisyphon on tank's pickup...if so remove it. You may want to get a cheap vacuum gauge and hook into fuel line just ahead of engine mounted fuel filter....is the fuel tank vent open(bugs,debris,etc)....