C3 1968 Holley leak

[Jim T.]

Have a Holley 650 6210 spreadbore double pumper on my L79. I usually know when the power valve needs replacing, but the current leak problem does not happen every time the the car sits overnight. Checking inside the carb the primary butterflys have gas residue the next morning and gas residue from the base of the carb and running down the intake at the base of the carb when it does leak. I checked the tightness of the fuel bowls and they are okay. When starting the car I can tell by the initial running that gas seeped into the intake, but it clears up quickly. What needs replacing?

[Clem Z.]

Re: C3 1968 Holley leak

pressure check the needles and seats and if they hold 9 PSI try dropping the float level about 1/16" to 1/8" below the sightplugs. a warped metering body will cause the same problem.

[Jim T.]

Re: C3 1968 Holley leak

Thanks for the quick reply Clem. This carb does not have sight plugs and I have to remove the fuel bowl to adjust the float level. Since you recommend pressure checking the needle and seat I think I will just replace the needle and seat when I remove the fuel bowl and check the float level.