Electric fuel pump, something’s not right..
 

6066 Club-

I have a ‘64 with the 305E, got in a trade. There was a bottle next to the battery full of fuel, problem #1. Guy said if it sat for a while he had to fill the web to get it to fire, ok. Well, sitting for a while is overnight, lol!! The carb seems like it loses prime when it sits. It’s the original carb with a manual fuel pump, but also has a Mr. Gasket electric unit as well. So, you turn the key and the electric turns on, but if you don’t initially fill the carb, it won’t fire up. Once you run it a bit, it’ll fire without a prime. So, why is the carb losing prime of bowl not staying full? Thoughts?

CAPT Dan

Re: Electric fuel pump, something’s not right..
 

Is the electric fuel pump hooked up behind the mechanical fuel pump?

Seems to me the fuel pump tries to prime the system but the manual fuel pomp 'blocks' the rest of the lines. I'd suggest getting rid of either fuel pump, keeping one in place.

Because of the electrical fuel pump, the mechanical pump failed some time ago?

Re: Electric fuel pump, something’s not right..
 

If the heat riser valve (on the right exhaust manifold) is stuck close it will heat up the intake manifold enough to boil out all of the fuel.

Re: Electric fuel pump, something’s not right..
 

Prowbar-
I have no idea why there are both pumps on there. Makes no sense to me either. My thing is, if the manual pump is bad, how does the **** thing run at all? Like maybe the manual pump got weak and instead of replacing it the previous owner had the electric laying around and just plumbed it in to "help out" the manual pump. I'm with you though, I think I'll try to eliminate the manual pump and see if it'll run of just the electric, which it should obviously.

James-
Fair point, I'll have to look into the riser. It would make sense that it would heat up and then while sitting boil the fuel from the carb. I had a '69 Dart that would boil the fuel.

I'm going to look at it closer this weekend, see how I make out, LOL!! Thanks again.

CAPT Dan

Re: Electric fuel pump, something’s not right..
 

Dan, I think it's a mistake to start following previous owners down the rabbit hole.
My suggestions: (thoughts)
1. Take off the electric fuel pump and throw it away. Get rid of the bottle of fuel.
2. Install a new correct mechanical pump. Keep the old pump as a spare but it could be ruptured.
3. Replace any rubber lines, replace filter. which should be just before pump.
4. After that, I will advice on a pump test before proceeding. If the test is good, then we will try to start motor. If it does the same thing, the carb probably needs rebuilt.
5. I don't know what "fill the web" means.
6. What brand is the carb? What is the number on it?
7. If you need help finding parts, you are in the right internet forum.
8. Please ask questions if you don't understand anyone's advice.
9. Lets take this one step at a time.

FYI: Your GMC is a not a "C" 1000, it's a 1000 series. "C" is for Chevy. More complete it is 1001 for short bed or 1002 for long bed.

The only one I know still available is Carter M3955. Don't buy an Ebay one.

Re: Electric fuel pump, something’s not right..
 

A friend of mine has an old 55 Chevy and had problems with fuel bleeding back into the system. He installed a small fuel pump on the system to prime the carb prior to set-up. The pump was put on a switch and triggered prior to starting truck up. he still has the manual pump which will pull gas through the electric pump. It seems to work very well. I've looked at doing the same as my system will back bleed and a shot of starter fluid and she fires up first try. If you try it without it and she doesn't hit a lick for a while. i have replaced fuel pump twice and still same problem.

Re: Electric fuel pump, something’s not right..
 

AZken-

1. Noted. I'll disconnect the electric pump and reroute the fuel line to the manual pump.
2. Ordered the Carter M3955 from RockAuto as you suggested
3. I'll put a sightglass filter right before the carb so we know she's pumping.
4. Noted. Hopefully with the new pump and sightglass filter I can verify fuel is flowing while cranking.
5. That was supposed to read "fill the carb," **** autocorrect.
6. I forgot to check the numbers, but it appears to be the original single barrel. I'm planning to install the Holley 2300/ 4412 as soon as I get the money.
7. I'm stoked that I found the forum for sure.
8. Thank you for the help!!
9. I agree completely, no need chasing the previous owner's issues.

And thank you for the correction on the model ID, I love the truck!! Still educating myself on them of course, LOL!!

Gwhizzard-

That appears to be what the previous owner attempted to do as well, except mine still has issues despite the electric pump being in place. Hoping that a new manual pump and eventually a new carb will solve the issue.

Thanks again all, just waiting for the parts now before I can move on.

CAPT Dan

Re: Electric fuel pump, something’s not right..
 

3. I always use the closed can, Wix type 33032 or 33033 depending on line size desired.
A pump is tested in other ways. We can discuss that if it doesn't start.

6. Should be a Bendix Stromberg WW 2bbl carb. Nothing wrong with that carb. It is designed for that motor. Nothing will be "better" and is a waste of time and money. Mike's Carburetor/mikescarb.com has the rebuild kit and 4 or 5 videos on them.

Dan, great responses, albeit 5 days.

Re: Electric fuel pump, something’s not right..
 

AZKen-

My bad on the late replies, works been crazy!! Anyway, my education continues. I took pics of the current carb, they should be attached. I didn’t find any numbers per se, hoping a visual identification is possible. Agreed though, it appears to be the original Stromberg. And you have a point about the carb, if it’ll start normal and run, fair that there’s no need to fix something that actually works.

CAPT Dan

Re: Electric fuel pump, something’s not right..
 

Number location photo