Holley Double Pumper Gas problems??

[Mopar-Charger]

I just rebuilt a Holley 700 DP 4778-2

I put it on, drove the car fine, once I got about 10 miles down the road it started to act up. I could only get it started by putting the pedal to the metal (getting the secondaries to squirt.) I just kept adjusting the float level until I could get it to start.

Once I get it started I can get it to run for about 30 seconds to a minute, then the carb dies and squirt fuel out of the primary vent tube. I can also hear the carb flooding (the fuel filter drains as the carb floods).

Once I start it again, same problem. I loosened the gas cap to see if that was problem, car ran for about 3 minutes this time, then shut off and died. Now when I try to start it, it starts up and dies seconds later, unless I get in the throttle about 20% to keep it alive. I don't see any leaks, only by the primary throttle plates when it floods.)

What can I do, What do I need to do to get my holley running right? If I can get the car home, I'm going to replace the Power valve (kit came with an extra) and see if that may be the problem?

I'm stumped, so what ever you guys need. Just ask away!

360
Headers
airgap intake
2.02 heads
timing is fine
ported vacuum (not manifold)
130GPM holley Fuel pump
stock tank
stock fuel lines
Rubber lines from pump to filter

 

[dieseldazzle]

What did your "rebuild" consist of? Did you verify gaskets against the old ones or the metering block orifices (spelling?)??

Vent tube sounds like needle and seat plugging if your float level is spot on.

 

[Mopar-Charger]

Just new gaskets all the way around. THe kit only had one set of metering block gaskets, and all the holes line Up do I assumed it was right.

Now what i'm facing is the primary float bowl is empty? I removed the needle and seat and still no gas going into it. THe secondary bowl seems like its getting gas, when I press the accelerator pump it sprays plenty of fuel into the carb, where as the primary is dry.

 

[69Bee]

Did you put the gaskets on dry, or use sealer? Is this carb NEW to you (no running history)? Maybe the front bowl is plugged/not drilled so fuel cannot enter it.

 

[dieseldazzle]

You rebuilt the carb but didnt install new needle and seat? Did you check for sunk float? Always stare and compare the gaskets for main body to baseplate and metering blocks there were many differences/variations broski.

 

[Mopar-Charger]

Yeah, now that I have it pumping to the primaries, it keeps leaking where the throttle plates meet the linkages? So youre saying I have a blocked hole due to wrong gasket? I was reading that it was a needle and seat adjustment problem?

I replaced the needle and seats with the kit.

I've always rebuilt carbs without any sealant.

 

[69Bee]

...I've always rebuilt carbs without any sealant.

Good, I made that mistake when I was 18, lol...

 

[Mopar-Charger]

Yeah i've never. THis was a $60 dollar carb I picked up at Moparnats. One problem i noticed pretty quickly was the the needle and seat hole threads were stripped. I pulled a bowl off a broken 750 vacuum secondaries carb I had. THe only difference was the accelerator pump hole was a bit smaller (figured it was better because I had a stutter as soon as it was pressed) I put that in and didnt have a problem.

I kept lowering and lowering the float level until I didnt have any leaks or problems. That seems to help it just fine.

One Thing I wanted to ask was I have a high out put motor running on 2 inch outlet flowmaster mufflers (don't ask why). I will be going to a 3 inch all the way back (budget problems - being an 18 year old). Would I feel a difference In performance? Prior to building the engine I had cutouts (pretty much stock engine with 4 barrel) and it would cook on the top end. No cutouts now, only running full system.

 

[68 HEMI GTS]

if it ran good then started acting up its probably a needle and seat issue. holleys do not like dirt.

 

[440+6]

I hope you set the floats at the bottom of the sight plugs, do you have filters in the bowl inlets? They might be clogged up.

 

[Burns69RT]

What's your fuel pressure? Double pumpers don't like anything more than 6-6.5 psi of fuel pressure. I suggest getting a fuel pressure regulator. A Holley one is like $40. I had the same issue on my 750 dp and that fixed the problem. I rebuilt the carb so I know it couldn't be anything else. My regulator is set to 5.5psi

 

[383man]

If you have fuel coming out the carb bowl vents then its flooding. Its either dirt on the needle and seats or the neddle and seats are bad and wont seal to turn the fuel off when the bowls are full. Or a bad float as I just did a Holley 750 DP that had a hole in the float and it filled with gas. You just need to find out why the needle and seats are not shutting the fuel off when the bowls get full. Ron

 

[WP29440SE]

Sounds like excessive fuel pressure

 

[WileE]

What's your fuel pressure? Double pumpers don't like anything more than 6-6.5 psi of fuel pressure. I suggest getting a fuel pressure regulator. A Holley one is like $40. I had the same issue on my 750 dp and that fixed the problem. I rebuilt the carb so I know it couldn't be anything else. My regulator is set to 5.5psi

First thing I would check.

 

[cryplydog]

Sounds to me like its full of crud, are you Sure its has a good quality filter and new?

 

[Mopar-Charger]

Brand new fuel filter (went in when I rebuilt the motor) about 300 miles ago?

Should i buy a fuel pressure regulator? Or get a fuel pressure gauge first?

 

[petieg383]

If fuel is pumping out the vent tube, your float might be toast. There is nothing in the bowl regulating the fuel and it just keeps pouring in. That was happening to me and the float had a pinhole in it and was half filled with gas. Pull the float and see if there is any gas in it. If so, replace it.

 

[Burns69RT]

I would get a fuel pressure regulator and a fuel log on your Dp with a gauge on it. That's how you'll set your fuel pressure.

 

[furyus]

Unless you have an electric pump pushing a boat load of fuel, the problem is in the carb. Remove the front float bowl, remove the float. Put it next to your ear. Shake it. Did you hear anything? If so, new float. If not, put it into water. Does it float? If so, it's fine. Re install float. Remove needle and seat. Is it dirty? Even the slightest piece of dirt will make it flood. How is the "O" ring? If it's damaged, it will flood. If ok, thread into float bowl. Turn float bowl upside down. Turn the needle and seat adjustment until the float is in the center of the bowl. You should see the two float mounting screws you just put back in. The top of the float ( now upside down) should line up across the middle of the screw heads. This is a good baseline float adjustment. Do the same for the rear float. If you cleaned everything spotless, it should start well enough to adjust.

 

[Burns69RT]

Depend on what mechanical pump he's running some run more pressure than others which cause to flood. That's why mine did that. I was getting way to much fuel pressure. I got a regulator and set it to 5.5, boom fixed it and never had a problem since. And I daily drive it as well.