KMS396

I recently went through the trouble of replacing my fuel lines and fuel pump. The car ran like a top before all of this, as I spent a lot of time over the summer getting the car running right after I bought it.

65 L76 Roadster.

When I fired it back up, I had fuel blowing out the primary vent tube. Ok, fine. Been there done that. Figured I got some trash in the lines and stuck the needle open. Took it apart, blew it out good, checked that the float wasn't sunk and could move free (I had already replaced this float and set the level perfect), put it back together and same thing.

I then put an old Edelbrock carb on that I had I could see fuel oozing from the top of the carb, and dripping into the primaries.

So, I put my hose pliers on the fuel line to restrict the flow some, figuring this pump is putting out too much pressure. Sure enough, runs just fine like that. Take the pliers off, and squirt.

Anyone ever had one of these original AC pumps (I got this one at Zip Corvette) put out too much pressure out of the box? Maybe the pushrod is not original and too long? I'm out of ideas. Maybe the pump is just junk.

Wasted my whole day messing with what worked perfect before, so my desire to put the car back to original and replace the perfectly working china pump with an orignal AC pump got the best of me.

Any ideas are welcome, and no, I'm not putting a regulator on this car

Subfixer

Common problem these days. Either the diaphragm return spring is too strong, or the diaphragm itself is too stiff.

I went through 3 pumps and ended up making one from the three that wouldn't overcome the float needles. If I remember correctly, I used the return spring from my old pump, a new diaphragm and new check valves.

KMS396

Thanks. It's not like that thing is a piece of cake to swap, so I'd love to not have to try 3 different pumps until ones works.

VetteRed1965

My went out in a parking lot...How many cars an hour later can you have up and going !

Frankie the Fink

If you aren't willing to put a regulator in the pump-to-carb fuel line then you'll have to either rebuild or replace the pump. The over-pressure situation isn't going to solve itself.

MikeM

Before I blamed the pump, I'd put a pressure gauge on the outlet line and see what pressure it is pumping and if it exceeds OEM spec.

Pilot Dan

Did you actually measure the fuel pressure?? You are looking for around 5 lbs pressure from a standard pump. I'd measure the pressure to confirm your problem IS the pump before proceeding. Pilot Dan

65 vette dude

Arthur Gould will rebuild your original pump, back to factory specs, or he will send you one he has rebuilt, and you send him your defective pump as a core. Tell him your problem and he will make sure your pump put's out between 4-6psi when you receive it........... http://arthurgouldrebuilders.com/

KMS396

Really? Man I thought it would just solve itself. There goes that idea!

KMS396

Everything I did confirmed it was the pump, but yes I eventually checked the pressure. Nothing else it could be.

KMS396

Thanks! Very helpful.

mrg

As a point of information, how high was the fuel pump pressure when you checked it? .. Thanks

KMS396

11psi

Subfixer

Two new pumps I bought were between 10-13 psi. The third had a check valve installed backwards. Using parts from all 3 plus my original that had the pin for the lever fall out, I was able to build a pump that put out 7.5 psi. Been in the car for about 3 years now.

KMS396

Wow, I'm glad you finally got it working right. I called ZIP, and as expected since their customer service rocks, there is already a replacement in the mail for me. Hopefully this one works.

I feel better today, as my rebuilt trailing arms showed up from Bair's, and they look awesome!

69_Shark

Congratulations!

Scott

Frankie the Fink

Well since that post was 1/2 decade ago I'm sure he solved his problem by now...

JF in MI

Maybe I'm over simplifying things here but; if it is 'rebuildable' (meaning you can take it apart) why not try cutting a loop off the pressure spring? Seems to me that if you had a pressure gauge to test it with you could test it in a vise before installation.

GTOguy

Again, this post is 5+ years old. Problem likely long since solved.