gas lost

[sg1747]

all the time i let may car sit for a day or two i go to start it and all the gas is gone in the front bowl.what am i missing.holly 780 69 z
john

[Keith Tedford]

I have had the same problem with our L78. Let the car sit for a day or two after a long run and the carb is basically empty. Fill the float bowls through the vent and the car starts right up. Start it and shut if off cold. A week later the car starts like it had been running five minutes ago. I added the GM oil baffle that snaps in between the heads. It keeps most of the hot oil off the intake. I also blocked the heat cross over, and double gasketed the carb to intake to slow down heat transfer. That helped quite a bit. I'm getting an aluminum heat shield that goes in between the carb and intake to keep more heat away from the carb. I believe that the carb and intake don't need that much extra heat for summer running. I never had this problem with the Q'jet on our 455 Lemans, even with the cross over open.

[Andy]

[ QUOTE ]
I'm getting an aluminum heat shield that goes in between the carb and intake to keep more heat away from the carb.

[/ QUOTE ]

I run one of these too with a 3/8" thick gasket that came with it. It is made by holley. I noticed a significant reduction in the temp of the fuel bowls on my holley 750 street hp after the install, and I'm running a super victor intake as well. I would definately recommend this. My car usually sits 5-7 days between each time I drive it, and I can get in it, pump the gas 3 times, and it fires right up.

[VintageMusclecar]

John;

Check your primary power valve and power valve gasket first. If either of them are defective it will allow fuel to drain through them as the carb sits. One very common problem is people using the wrong power valve gasket for the style of power valve being installed which all but guarantees an issue. This is most common when using "generic" power valves normally found in less-expensive rebuild kits.

Another possible issue is a warped metering block surface on the main body of the carb, or a warped metering block. Either can also cause fuel to weep internally and allow the carb to drain.

The carb heat shields are always a good idea as well.

Eric