Guys, I'm having a problem with gas evaporating from my carb between starts. The setup...Q-jet carb (I rebuilt), spread bore to square bore adapter, cast iron intake. These pieces are bolted together with the respective gaskets installed in between. The intake seems to be getting hot and that heat is transfered to the carb, speeding up evaporation process. First thought is to block off the heat cross over path in the intake that runs along the front of the first two inlets with a high temp RTV. Then I thought I could get a new set of gaskets and they may include a heat blocking insert like some of the sbc's come with...answer = nope. Should I just stick to using the RTV on the top of the intake or would there be a good way to block the heat from the source, at the base of the intake? FYI...the heat riser valve in the exhaust manifold is stuck in the open position. Motor runs in the proper temp range. I realize that there are many different carb/intake setups that may be preferred over what I have at this time and I may explore those later but at this time it runs well and that's all I'm looking for...just tired of having to prime the carb between starts. Thanks, Alex
Are you running the correct fuel filter in the q jet inlet,I believe they have a check valve to prevent drainback
If it's not running lean and timing is rite on manifold heat shouldn't be a problem. On the Q-Jet rebuild I remember something about sealing off something inside so gas does not leak, sorry I can't be more specific it's been awhile ...................................
A friend of mine had the same issues with a Edelbrock performer carb and intake on his '77 Vette. He installed a carburetor heat insulator gasket and that solved his problem. simple, fast and cheap! Rik
Chances are that the Q-jet is leaking down thru the well plugs at the bottom of the float bowls. Common problem usually solved by using epoxy to seal them. JB Weld comes to mind. Porous casting also can be the culprit.
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