2001 no fuel flow

[Neal]

I am new here and to carting so hello everyone. Now, I have a problem. My '01 295cc has no fuel flow. How does the fuel pump work? I see a line coming from the crankcase to the pump. Does it use pressure pulses from the crankcase to work the diaphragms? What should the pressure be on a gauge? I have no suction on the supply side of the pump. I adjusted the valves to make sure that was already done. Thanks in advance for the help.

[WILD-BILL]

The fuel pump works on a vacuum pulse from the intake manifold.

Before trying a replacement pump check to see if the filter or line is clogged.

[ez go go]

My 00 is the same as yours. Mine uses blow by from the crankcase that works the diaghram inside the pump causing a suction on the pickup inside the tank then feeding back through the pump into the carb... I don't know about pressure values but you should have a steady stream pumping out under acceleration when the hose is disconnected from the carb.

[Neal]

Thanks for the welcome! I have checked the hoses, replaced the filter, checked the plastic pick up tube in the tank, adjusted the valves, replaced the spark plugs, and air filter. What should the compression be on this motor? I have not checked it with a gauge yet but I do know that I can completely seal the compression with my fingers while cranking on both cylinders. Are these known for piston or ring wear issues? I figured that if the compression is too low then I may not have enough blow by pressure to work the pump properly. I disassembled the pump and found nothing wrong but I could have missed something. I am at a loss so if I knew what the compression should be that would point me in a general direction. Thanks again!

[Neal]

I have 95 psi on one cylinder and 105 on the other. Thinking about a low pressure electric pump hooked up to the same signal that causes the coils to be powered up?

[DOOmsman]

See the stickie "fuel pump" at the top of the gas Yamaha section.
i had to clean my fuel pump.

[ez go go]

Originally Posted by Neal

I have 95 psi on one cylinder and 105 on the other. Thinking about a low pressure electric pump hooked up to the same signal that causes the coils to be powered up?

Your onto something with that comp... It's way to low, and yes this could affect some of your fuel issues. If you have already adjusted your valves correctly then you have ring issues that will require some attention. These engines are tough, but rings are a common fix. Boring and oversizing the piston may also be in order depending on cylinder condition.

[Neal]

Last night I hooked up an inline low pressure fuel pump in place of the diaphraghm unit. I powered it with the same wire that energizes the solenoid from the throttle pedal so it will only run the pump when the engine runs. I most likely will wait until this winter and do a ring job to bring back the performance but it should get us by for now.