fuel pump question

[DIXONBOY]

On my FE engine I have a mechanical punp that was pumping 5 psi and my bowl would run dry. (2bbl) I put and electric pump under my cab (without removing the mechanical -kept it inline) and it went to seven psi. Runs great now. What I want to know is it ok to have both pumps going like that or will that 7 psi make my mechanical pump leak into my engine.

[fordman]

it depends on how much pressure the electric one is pumping. it might blow out the mechanical one. but then again if it does you may never know it. if the electrical one is that strong.

[Dragon]

Don't run both, the mechanical is not doing any pumping, the electric pump is just going right thru it. You are headed for a mess if the pump diaphragm ruptures the gas will fill your crankcase.

[HOWDY69]

My stock mechanical puts out 6.5 psi.

[DIXONBOY]

Well I put my guage on it and pulled the top of my carb off wile it was running and pushed the neddle down so no gas would come though and it never whent past 5psi. Its a new pump does that mean its bad or it because its trying to suck through the electrical pump. When I was doing this test the electrial pump was turned off.

[HOWDY69]

Well I put my guage on it and pulled the top of my carb off wile it was running and pushed the neddle down so no gas would come though and it never whent past 5psi. Its a new pump does that mean its bad or it because its trying to suck through the electrical pump. When I was doing this test the electrial pump was turned off.

I disconnected the fuel line to the carb, connected the gage, and had my son crank the engine. Because our readings were taken in different manners I do not know if they can be compared.

[Dragon]

Well I put my guage on it and pulled the top of my carb off wile it was running and pushed the neddle down so no gas would come though and it never whent past 5psi. Its a new pump does that mean its bad or it because its trying to suck through the electrical pump. When I was doing this test the electrial pump was turned off.

Arrrrrghhhhh

[DIXONBOY]

Arrrrrghhhhh? Whats that for ---

[DIXONBOY]

I guess what im trying to say Is Id rather use the mechanical one and take the electric one off. But if 5 psi is not enuf which it seems like its not then I will un hook it and run the electic one. Im at work right now so all I can tell you Is what Ive done over the weekend.

[fordman]

to get a acutrate measurement you should remove the electric pump from the lines that way it can properly be tested. i think i heard the mechanical pumps run between 5-7. electrics run higher.

[Dragon]

I would get the mechanical one off and through it as far as I could. Like I said if the diaphragm ruptures the gasoline will pour into your oil pan and it won't stop because you shut the engine off. It will just keep siphoning from the gas tank.

The last time that happened to me I was lucky The carb lost fuel The engine died and I knew it was fuel death because one pump of the pedal and the engine caught and died. I turned off the ignition and turned the corner and costed to a stop out of gear. By the time I got a clamp on the fuel line to close it my dipstick was 2 inches above full because of almost a gallon of gas in my engine. That gas would have wiped out my bearings in nothing flat.

[DIXONBOY]

Ok i'll take it of tonight. Thanks for the help.

[fordman]

well if you take it off you need a block off plate. if you dont have one you can just route the fuel line around that pump and not have it hooked up.