Too much gas / new pump

[BigMacDave]

Hello all,

My first post here, i so hope i don't look silly.

I bought a 1978, it was not running. after a lot of going over, we figured out it was the internal fuel pump. apparently they had the conversion done awhile back and the owner i bought it from didn't know.

it is very difficult to find an internal fuel pump with low pressure, so i bought an external one (like the one i have on my bug) it is a Holley that has a psi from 1.4 to 4 max.

the plumping went great, i hooked the leads up to the wires running from the dash switch and BAM it pushes a ton of gas and basically floods it out before i can even start it.

The instruction on the pump just say wire it to a 12v with the key on, (which is basically what that is, i turn the key on and hit the switch) but the carb is just getting way too much gas.

what am i missing? i saw on several post i game using the same setup as others so I'm not sure whats happening.

Thank you

David

p.s. after the flood dies down and i don't turn the pump on, it sounds great for a good 15-30 secs before it runs out of gas. very close to maiden voyage

[Ramzi]

internal fuel pump

What do you mean by internal?
Where is the pump you are trying to install located?

R

[BigMacDave]

it used to have an submersible fuel pump. obviously a shade tree mechanic setup. the pump went out. i tried to find that pump but it was next to impossible as there are no markings on it. so i purchased a new sending unit (to replace the one that was cut for the fuel pump) and also purchased an external pump.

Literally all i did was put the new sending unit in, and added the pump (in the truck at the angle recommended) and used the same wires coming off the switch that used to lead to the internal pump.

when i turn the key to ON i can toggle the switch on and off and the pump works fine. issue is, when the pump is on before it has time to start, i have fuel leaking like mad from around the carb, i assume it is just too much pressure, however i can't see how, as nothing has "changed" and the new pump is a 1.5 to 4. could it be something deeper in the carb itself? i assume the pump should stay on all the time which would lead me to believe something is not "holding back" the fuel... the unknown is how long the car sat. but like i said, it fires right up when its not flooded

am i on the right track?

[Nanonevol]

I'm no expert but shouldn't the float jet in the carb limit how much is getting through? Probably worthwhile to take apart and clean up the carb. Check the operation of the float and the condition of the float needle and seat.

[BigMacDave]

Ok, what else i can see is the return is not being used. the fuel line is connected o the sending unit and goes thru the trunk wall, but it is hanging on the other side

[BigMacDave]

Nano, thats what I'm kinda thinking also. BUT what does the pump do with the extra pressure if the return is not being used? and its puzzling, because i assume it "used to work" the way its set up.

of course i have no real way of knowing

[BigMacDave]

ok, not sure what they did. for grins i bypassed the switch and just ran the 12v straight to the battery. works like a dream. car runs strong. guess my next task is to either trace that wire back or run a new one. also, i think I'm just gonna wire it to the ignition anyway. car is running, pump is on. I have seen a few people talk about the oil switch method, has anyone had any luck with that?

thank you

David

[Ramzi]

One suggestion is check the output pressure of your pump.

When I bought my 66 124 one of the 1st things I did was to replace the mechanical fuel pump and install a new carb, Cranked the car and fuel poured out of the float bowl with in seconds. I checked the float and the needle and seat and the checked ok... Scratched my head for a bit before Csaba suggested checking fuel pressure...as it turns out the 50 year old mechanical pump had a stuck pressure release ...and I was getting 30 psi to the carb... 2nd pump worked like a charm

Also verify that your return line is clear.

R