Electric fuel pump

[86swb]

I am thinking about taking off the manual fuel pump and replacing with an electric fuel pump. This will be on my 84' 305 small block and would prefer a quiet as possible pump. Want to get away from having to pump the carb most of the time I start the engine. Which electric pump would be best for my 305? Any help would be really appreciated.

[SkinnyG]

I have an AC Delco EP12S pump which is noisy enough to be heard if the engine is not running. I don't notice it after that. I mounted it inside the frame rail at the lowest point of the frame. I went through two brand new mechanical Carter pumps within three years.

I have run a few Facet pumps on a different vehicle, but went through two of those in short order before I bought the Mr. Gasket replacement. I kept the EP12S in the trunk because I expected the Mr. Gasket pump to fail quickly as well, but it's held up fine.

[mongocanfly]

I ran mr gasket for several years with no issues..

[raceman6135]

If you want as silent as possible, stay with the mechanical fuel pump, and then figure out why you need to "pump the carb" in order to start it.

It sounds like your carburetor's fuel bowl is draining when the engine is off. If you are running a Quadra-Jet carburetor, it's fairly common for the well plugs on the bottom of the carb to seep fuel and empty the float bowl. The usual fix is to epoxy them, as shown in this image found online:



Sometimes, the engine and ambient air temperature is so high that the fuel percolates and/or evaporates after the engine is shut off such that the float bowl(s) is empty the next time you go to start the engine. If this is the case, having an electric fuel pump pressurize the system a few seconds before cranking the engine to start may help, but a 1/2" thermal spacer such as this phenolic version is less expensive and easier to install than an electric fuel pump.



However, sometimes the carburetor settings are not optimized and "pumping the throttle" is used to set the choke, providing a temporarily richer mixture that aids in firing the engine up. If this is the case, the type of fuel pump isn't going to make a difference.

[86swb]

I have an edelbrock carb. I only have this problem after the truck has been sitting over night or just sitting for some time etc. I should have put this in the engine section.

[wilkin250r]

I would be a little surprised if the float bowl is empty overnight, it's very likely you're setting the choke. Try letting it sit overnight, then push the pedal to the floor once, not fast, but not real slow either. It's not a "pump", you're moving linkages and springs in place to set the choke for starting.

If it starts, then it's perfectly normal, this is actually the recommended starting procedure, it is DESIGNED that way. One push to the floor, release, and start.

I've known a few people that have had good luck with electric pumps, and LOTS of people that have had bad luck with them. Just look at this thread. It's filled with replies like "I went through six electric pumps in four years, I'm really surprised my last pump has lasted this long..."

[El Dorado Jim]

i have added an in line electric fuel pump on several of my trucks, turn it on to get gas up to the carb,truck will start right up, you can shut the electric pump off after that or leave it running, wont hurt a thing....leave your mechanical pump there

[cadillac_al]

If your mechanical pump is weak it will be harder to pull gas from the tank. Eddys don't usually leak but they can boil some fuel out. If I let any of my trucks sit for a couple weeks and things get dried out, the fuel pump will start pumping fuel into my fire hazard fuel filter in about 5 seconds. When I had old worn pumps it would take closer to 15 seconds to get some gas dribbling through the clear filter. If that choke is snapped shut in the morning it shouldn't take any more than 10 seconds to start. I never pump my Eddy carb truck. Just once to set the choke and twice if it's been a couple days.

I have thought about an electric helper pump for years but once I got good working mechanical pumps the trucks work well enough for me. When I was thinking of electric pumps my mechanical pumps were worn out.

[86swb]

All of you have been a great help. Thanks. Now just have to make up my mind on which way I want to go. Sorry it took so long getting back with you guys but had some health trouble with one of my son in laws. But now all is good. Thanks again for all your advice.

[Tucson38]

Originally Posted by El Dorado Jim

i have added an in line electric fuel pump on several of my trucks, turn it on to get gas up to the carb,truck will start right up, you can shut the electric pump off after that or leave it running, wont hurt a thing....leave your mechanical pump there

Sounds like a great solution (I'm having the same problem with my Edelbrock).

Does the addition of this pump impede the normal flow from the mechanical pump?

[wilkin250r]

Originally Posted by Tucson38

Sounds like a great solution (I'm having the same problem with my Edelbrock).

Does the addition of this pump impede the normal flow from the mechanical pump?

From what I understand, this isn't a simple yes or no answer, but more like a "it depends on the pump". I've seen many testimonies of people running a setup like this with great success, but I've also seen several with people having problems. I've even seen some references to people talking about factory setups with inline electric and mechanical pumps.

For the life of me, I can't seem to find specific brands, nor any kind of specs or options for a "pull-through electric fuel pump".

[cadillac_al]

Back in the 70's, The Chevy/GMC C70 trucks with the 427's had electric fuel pumps in the frame rail. I can't remember if they went to a mechanical pump or directly to the carb. I guess those things could pull fuel out of a fuel tank. They were slightly smaller than a 12 oz beer can. Those may still be available. Also The GMPP catalog has a very nice electric low pressure fuel pump for around $50. Come to think of it I bought one for my truck a couple years ago and never used it.

[86swb]

I guess putting a electric fuel pump by the tank would pull the fuel flow faster and cause the mechanical pump get fuel to the carb faster? But then you would have to turn the electric pump off?

[El Dorado Jim]

you want to put the electric pump as close to the tank as possible, these pumps push rather than suck.....you can have it on a switch, use it to start the truck then shut it off, make sure you have it hooked to a source that is only hot when the key is on....otherwise you could accidentally leave it on when the truck is turned off!then you have an engine full of gas!!!! ask me how i know!!! lol

[cadillac_al]

With all my chevy v8's with good fuel pumps, once the oil pressure gauge goes up the carb is also getting fuel. That's when I give it a couple pumps. If it's been sitting for a week or more I don't waste my time pumping the dry accelerator pump while the carb is dry. I wait for the oil pressure then a couple pumps is all they need. If it has only sat overnight then one or two pumps and they will fire right off; before the oil pressure, which isn't really desirable in the winter time.

[Keith Seymore]

Originally Posted by El Dorado Jim

i have added an in line electric fuel pump on several of my trucks, turn it on to get gas up to the carb,truck will start right up, you can shut the electric pump off after that or leave it running, wont hurt a thing....leave your mechanical pump there

This is what I do on my race cars. That way I can drive around normally on the mechanical fuel pump but turn on the electric "pusher" pump during periods of high demand (like during the burnout and down track) and for priming if the vehicle has been sitting for a long time or after a carb removal.

K

[Tucson38]

Originally Posted by El Dorado Jim

you want to put the electric pump as close to the tank as possible, these pumps push rather than suck.....you can have it on a switch, use it to start the truck then shut it off, make sure you have it hooked to a source that is only hot when the key is on....otherwise you could accidentally leave it on when the truck is turned off!then you have an engine full of gas!!!! ask me how i know!!! lol

Good tip, thanks.

[Tucson38]

Originally Posted by Keith Seymore

This is what I do on my race cars. That way I can drive around normally on the mechanical fuel pump but turn on the electric "pusher" pump during periods of high demand (like during the burnout and down track) and for priming if the vehicle has been sitting for a long time or after a carb removal.

K

So you have the pusher pump plumbed into the same fuel line as the mechanical pump? Any problem with the mechanical pulling fuel past the pusher pump?

[Keith Seymore]

Originally Posted by Tucson38

So you have the pusher pump plumbed into the same fuel line as the mechanical pump? Any problem with the mechanical pulling fuel past the pusher pump?

Correct, and no issues.

K

[Tucson38]

Thanks, appreciate the input.

[86swb]

Thanks guys, getting a lot of good information to think about.

[Keith Seymore]

Originally Posted by Keith Seymore

This is what I do on my race cars. That way I can drive around normally on the mechanical fuel pump but turn on the electric "pusher" pump during periods of high demand (like during the burnout and down track) and for priming if the vehicle has been sitting for a long time or after a carb removal.

K

Just to elaborate a bit more, I use a Holley red pump at the tank. Both my vehicles have 1/2" fuel lines going forward.

The GTO has a toggle switch under the dash: flip the switch for a few seconds to prime, pump the gas 6 times and it will fire right up. It's been set up like this since the mid 60's. It is a 389 tripower four speed car and has gone 12.20's with this setup.

http://www.hotrod.com/articles/5000-...-still-family/

The Chevelle is similar but is wired to the (former) rear window defog toggle switch. This year marks 38 years racing this same car; it's gone 9.80's in ideal conditions with the super tune up but likes to go 10.20's/10.30's in the heat of the summer.

http://www.superchevy.com/features/s...hevy-chevelle/

K

[SkinnyG]

So why not have that electric pump at the tank going all the time, or even exclusively (no mechanical pump), instead of two pumps?

[Keith Seymore]

Originally Posted by SkinnyG

So why not have that electric pump at the tank going all the time, or even exclusively (no mechanical pump), instead of two pumps?

1) Noise
2) Durability (wear and tear) on the electric pump. Mechanical pump has much better life expectancy
3) Depending on the pump you might have to add a fuel pressure regulator. (I deadhead mine against the carb float; since I only use it during periods of high fuel demand then no regulator is needed)
4) If the electric fuel pump quits you are dead in the water.
5) Stock appearance with the mechanical pump

off the top of my head.

K

[D13]

Whereas I was looking at doing an 87 in-tank TBI pump with a low pressure regulator on my carb job. But I suspect a cheap electric with check valves to prevent backflow would be perfect for the old Monojet on the 250.

I am going to put the later model electric lift pump on the 6.2l diesel, with an additional override switch. So much easier to prime the filters.