Chevy van fuel pump

By installing a fuel pressure regulator that has a return port.

Or just put the pump at the tank where an electric belongs and forget the return. I would question WHY he wants the hassle of an electric pump.

Could I ask Why? The factory pump is FAR easier to work with than an electric. As for the three lines you are correct. One is fuel from tank, one is fuel to carb and the other is a return to tank line. The return line is a good thin on a van in particular due to them normally having tight engine bays and running warmer under the hood as a result. The extra heat makes them more prone to vapor lock. If you really need an electric pump buy it and a carb rated pressure regulator with a return line fitting at the same time.

/The van sets in storage for fairly long periods and I often have to start it with a dry carb. I want to fill the carb without cranking the engine too much. Actually already have the electric connected through a relay that is active with the engine in run. I can also activate the relay via a toggle switch with the engine off. The t5wo circuit are isolated with diodes. I have tried it with the return plugged and didnt see a problem. It worked as expected. With an empty carb the pump ran for a few seconds then went quiet. Engine fired up easy. Yes vapor lock was one of my concerns about disconnecting the return line. Who makes the regulator like you are talking about, Ive seen the ones for fuel injextion wuth the return but not for a carb. / /Jimmie

/Jimmie

What you could do would be to set it up like the older Fords were. They had a primer pump and the main pump.

Basically they just added an electric pump in parallel with the mechanical pump. You need the pump you already have. Two Y fittings that fit the fuel lines and two check valves. Connect the electric pump so it bypasses the mechanical pump. The check valves go inline so that when the electric pump is off the fuel cannot go backwards.

With this you can push the prime button and fill the carb and start the engine. You might want to look at an oil accumulator as well. That way when you hit the prime switch it would fill the carb AND pump oil through the engine so it doesn't start dry.

All he really needs to do is put the electric pump near the tank, (where it belongs) and push THROUGH the mechanical pump. No plumbers nightmare is required. BTW, what the hell Ford had a hand primer? Back in the 30's or what!?

F800 with a Cat 3208.

Sounds like what I will do and replace the switch I have with a momentary push button.

Jimmie

I'd fix the leaking carburetor because all that gasoline leaking out isn't doing your rings and cylinder walls any good.

Great idea, electric pump running 7 psi, year or so down the road, diaphragm goes to hell in mechanical pump, so the electric pumps gas into the crankcase, bye bye mains, rods, cam bearings etc. The other consideration being missed in all of this is how does the system know to shut the fuel pump off in case of an accident? Or do we just accept fuel spewing from a ruptured fuel line till the tank runs dry, or we get ignition?

Whitelightning

He SAID it was only for momentary priming use. So get off me. If he would have wanted it for full time use, I would have recommended bypassing the mechanical pump.

Most of the C series have a primer system on them if they run a gas engine. So did some of the larger F series gas models.

No his first post said he wanted to REPLACE the mechanical with an electric. In later posts he said he had them in tandem with a relay and switch. Also keep in mind someone else six months from now maybe reading these things looking for a solution and say, hey all I need to do is run it through the mechanical pump.

Whitelightning

And it would work fine that way. The diaphragm failure mentioned before is just as serious with or without the electric. And just as unlikely in any event.

Found the electric will push hrough the mechanical pump but the mechanical pump will not draw through the electric. The electric has to have a one-way bypass. This is really getting complicted with both pumps but I think I have found a solution. No electric pump. From what I have seen while disconnecting and connecting the pumps several times is that fuel line directly behind the stock pump gets air in it after setting a long time. At least this is what I suspect is happening because gravity does not push fuel all the way to the pump..It may when the tank is full I installed a check valve near the tank where I had the electric pump. So far OK but I think I may have to let it sit for a couple of months to se if this is a good fix. Oh yeah, the only check valve I could find is meant for AIR. Is this OK.

Jimmie

I would do some checking before you push THROUGH a mechanical pump. Some pumps will blow seals when you apply pressure to the inlet that normally operates in a vacuum.

James