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Electric fuel pump question

k2mslskier

k2mslskier

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Is an electric fuel pump needed for a carb on a seemingly stock 350? This 76 Burb I recently got has one and it’s noisy as f***. I don’t see a reason for it since it has a mechanical one as well.
Should I just pull the electric?
 
An electric pump isn't necessary for a stock-ish carb'd motor, it's likely there because the mechanical pump doesn't work and installing an electric pump is easier.
 
nvrenuf said:
An electric pump isn't necessary for a stock-ish carb'd motor, it's likely there because the mechanical pump doesn't work and installing an electric pump is easier.
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Thanks. I found it strange that they have the electric going into the mechanical and then to the carb. But I’ll yank that sucker today. Have a new mechanical on the bench that was going to go into the k20, but that can wait.
 
Electric fuel pump can make a nice anti-theft unit. Without the electric pump running, there is enough fuel to start the vehicle, drive it about 100ft, and then it dies in the middle of the road.
Thieves bail out and run...too high profile to be on the street with a stalled out vehicle, and no time to diagnose.
Saved my truck THREE times! ....so something to consider before you go back to mechanical.
 
Ned Kelly said:
Electric fuel pump can make a nice anti-theft unit. Without the electric pump running, there is enough fuel to start the vehicle, drive it about 100ft, and then it dies in the middle of the road.
Thieves bail out and run...too high profile to be on the street with a stalled out vehicle, and no time to diagnose.
Saved my truck THREE times! ....so something to consider before you go back to mechanical.
Click to expand...
Haha. Yeah I found that out yesterday while tinkering with it. Found a semi hidden toggle under the dash...”hmm, I wonder what this does?” Click....electric pump goes quiet, a minute later the engine starts to die. check!
 
My truck would not perform at highway speeds under load with a mechanical pump. It would hesitate buck and stumble 40 to 60+ in overdrive. Sometimes even 3rd.
I put 2 ac Delco mechanical pumps 40gph, tried blocking return, and 1 jegs 80gph mechanical pump. Now I have a Holley red label electric with extern regulator and a return to tank.
If the engine died with electric pump off, current mech pump is no bueno.
Diaphragm may have failed. Check your oil.
I hope your mechanical pump works out, this issue frustrated me for quite awhile. I blame ethenol.
 
Wes Harden said:
My truck would not perform at highway speeds under load with a mechanical pump. It would hesitate buck and stumble 40 to 60+ in overdrive. Sometimes even 3rd.
I put 2 ac Delco mechanical pumps 40gph, tried blocking return, and 1 jegs 80gph mechanical pump. Now I have a Holley red label electric with extern regulator and a return to tank.
If the engine died with electric pump off, current mech pump is no bueno.
Diaphragm may have failed. Check your oil.
I hope your mechanical pump works out, this issue frustrated me for quite awhile. I blame ethenol.
Click to expand...
Will do. Thanks.

Edit: Correction on them being connected. They are not. Will still be yanking the electric and replacing the mechanical this week.
 
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i read direct injection needs 3000 p.s.i.

"regular fuel injection" needs 15 to 160 depending on type.

In some cases carb only needs 2 lbs. Of course normally carb needs 4-8 ish.
 
But yeah, if the truck in question is a stock L48 350 with q-jet, then i'm thinking 4-6 lbs. And an electric is necessary.
 
vandelay industries said:
But yeah, if the truck in question is a stock L48 350 with q-jet, then i'm thinking 4-6 lbs. And an electric is necessary.
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On further inspection my VIN says I should have a 400 in there but I’m not so sure that’s what’s in there now.

How do I tell without pulling the heads and measuring the bore?
 
A 400 SBC has a "half moon" cutout on the harmonic balancer and also uses a flexplate with a balance weight...
I think its the only externally balanced "old style" SBC.

The 400's also have 2 freeze plugs on the sides of the block..350's had 3..
 
On this carb motors we've actually strapped a gas can on the roof and used gravity to feed the carb to get home when the mech fuel pump died. Ghetto but it beat walking....:saweet:
 
Magikal said:
On this carb motors we've actually strapped a gas can on the roof and used gravity to feed the carb to get home when the mech fuel pump died. Ghetto but it beat walking....:saweet:
Click to expand...


One of the guys who worked at the junkyard limped his Ford pickup to the yard after its fuel pump died by dumping out the windshield washer fluid tank and pulling the hose to the squirters off the windshield ,and put it over the air vent tube in the carb's float bowl..
We'd run cars in the yard on gravity feed many times before ,but never thought of using the windshield washer pump as a substitute fuel pump!..(We wondered just how much of a fire hazard this could have been,seeing a washer pump isn't exactly rated for flammable liquids!)..

He said he could go about a mile before it would start starving for gas,and he'd have to push the button in the wiper switch to refill the bowl..he drove it ten miles that way,said he had to siphon a gallon out of the gas tank at the hose feeding the fuel pump and got a mouthfull of gas in the process!.but he made it to work and was able to get a new fuel pump and install it ..
 
Since the original question has been resolved, more or less........

Then if i could hi-jack the thread for a moment:

Is it ok to run/pump water thru an electric fuel pump? This is for a temporary project.
 
I suppose it'd work for awhile,depending on the type of pump--the "solenoid" type would likely seize up eventually maybe,because water has no lubricant properties..(but then gas doesn't either really)..the vane type pump probably wont be as fussy..but once the pump dries up inside rust will likely form on internal parts and make it fail or at least not be very reliable as a fuel pump again..

Maybe you can use a washer pump or a RV water pump for your project instead ?..
 
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