Help guys!! 750 Holley Double pump over flowing on secondary side, Gas everywhere!!

[dzamora28]

Hi guys,
I just started my 78 Trans Am after a 2 year sleep. My Holley 750 double pumper is over flowing gas out the vent tube on the secondary side. My float is good, i stuck it in a bucket full of water and it stayed a float. I put a new needle and seat. The bowl is clean and the float moves freely, I've even adjusted it so it would close with minimal gas inside the float and still overflows. The overflowing is only occurring on the secondary side. I also swapped the fuel filter with the 2 inch canister type filter from Mr. Gasket to reduce pressure from the fuel pump and the overflowing still occurs.



Do you guys think its my fuel pump? Too much pressure? Let me know what you guys think, I don't want to spend anymore money on this particular problem. I do have an extra fuel pump, should i change out my fuel pump?

Any input is gladly appreciated. Thanks guys.

Danny

1978 Trans AM
Poncho 400
T-Top
4 speed

[forcefed68]

With the car running (know its hard with fuel spraying everywhere) can you adjust the float level down any further to see if that fixes the problem? Also, is it possible when you installed the new needle and seat assembly that the o-ring got torn or snagged? That's happened to me once or twice, forgot to lube them. Let us know.

[forcefed68]

One other question, is it a mechanical or electric pump? Do you have a gauge? Sounds like a carb problem. I doubt a pump problem would only cause one side to flood like that.

[68sixspeed]

Did you check where the needle and seat go into the bowl? I'm wondering if there is some debris, casting flash, etc that might be letting fuel by. Also make sure you have no more than 7psi or it can bypass the needle/seat.

[jjump59]

just because the float floats in water doesn't mean its good. shake it back and forth close to your ear to see if its got fuel in it. if it does, it needs to be changed.

[Vegas69]

Fuel is getting past your needle or your float level is to high.

[TheJDMan]

Check the power valves.

[Shaker455]

Hi guys,
I just started my 78 Trans Am after a 2 year sleep. My Holley 750 double pumper is over flowing gas out the vent tube on the secondary side. My float is good, i stuck it in a bucket full of water and it stayed a float. I put a new needle and seat. The bowl is clean and the float moves freely, I've even adjusted it so it would close with minimal gas inside the float and still overflows. The overflowing is only occurring on the secondary side. I also swapped the fuel filter with the 2 inch canister type filter from Mr. Gasket to reduce pressure from the fuel pump and the overflowing still occurs.

Do you guys think its my fuel pump? Too much pressure? Let me know what you guys think, I don't want to spend anymore money on this particular problem. I do have an extra fuel pump, should i change out my fuel pump?

Any input is gladly appreciated. Thanks guys.

Danny



1978 Trans AM
Poncho 400
T-Top
4 speed

Danny,
Doesn't sound like you tested the float right?

Is it a brass float?

You need to weigh it down in water to see if it takes on water.

I recomed you replace it with a nitrophyl float...less prone to failure.

Your pressure should be 6.5 psi