fuel pump pulse side

[199675hpforce]

Is this vacuum that operates fuel pump and or positive psi to operate. Connects to engine block and or cyl? Trying to figure a way to test fuel pumps without running the motor. I understand you can run the motor pull hose closest to carbs see if it pumps good fuel or sputters. Hook separate fuel tank to carb have friend pump bulb to keep motor and do reading on FP.

 

[1983rinker]

Re: fuel pump pulse side

Put a inline filter from the pump to the carbs. the clear kind.

 

[Frank Acampora]

Re: fuel pump pulse side

1996 Mercury Force? Fuel pump uses BOTH vacuum and pressure to move fuel. When the cylinder is inducting air, the pump diaphragm for that cylinder is under vacuum. When the piston moves down to compress the charge and blow it through the bypass ports, the diaphragm is under pressure. Check valves keep the fuel moving in the correct direction.

I believe the pump should deliver between 2 and 6 PSI.

 

[john from md]

Re: fuel pump pulse side

You cannot test the fuel pump without the engine operating as the vacuum and pressure impulses are part of the process. Hooking up external air and vacuum would only tell you that the diaphram is moving.

 

[199675hpforce]

That is neat filter!

That is neat filter!

Going to get one is it glass? My stocker is white plastic and hard to see whats going in. Got my rig running fantastic now guess a sticky float needle hanging up caused the stalling. Seems my fuel pump is working fine and ive replaced that couple times already. Guess sticky year old fuel is cause or maybe ethanol.