Carburetor Base Gasket not Sealing

[lastdime]

I just rebuilt my Super Cobra Jet 460 but am having trouble with the carburetor gasket not sealing. When I spray carburetor starter fluid at the base of the carburetor the engine revs. Sure sign that the gasket isn't sealing. I tried two different gaskets, checked to ensure the surfaces of the Quick Fuel carburetor and Toker II manifold are clean, but still no luck. I don't dare tighten the bolts anymore for fear of striping them. Any suggestions?

[Gaz64]

I would take the carb off, remove the gasket, refit the carb on the studs and see if the carb does sit flat, and does not rock side to side, front to back, and diagonally.

Being a Quick Fuel, I doubt the carb is a problem.

If you are using studs and nuts, you would generally break a mounting "ear" off the carburettor before stripping a stud.

Does your carb have a billet or cast throttle body?

Are you sure you have a real vacuum leak, and not just the tiny vacuum leak that many have at the throttle shafts?

Gary

[Ron61]

What Gaz said makes sense. You might also check your studs if you use them and make sure that they are all seated all the way.

Ron

[Antny]

Is there sufficient thread on the studs above the carb ears to allow you to tighten the nuts properly?

[lastdime]

Thanks for the suggestions. There are no studs, just bolts that screw into the intake manifold through the billet carburetor base. Both intake manifold and carburetor are new and clean. I will remove the carb and gasket and see how the carb mates to the manifold. As far as a real vacuum leak, I will double check that and see what I discover.
Update to come.

Thanks guys.

[133bus]

Is it possible that there is an amount of stray over spray that is just going into the carb with the air...steve

[Phill Pollard]

Originally Posted by lastdime

I just rebuilt my Super Cobra Jet 460 but am having trouble with the carburetor gasket not sealing. When I spray carburetor starter fluid at the base of the carburetor the engine revs. Sure sign that the gasket isn't sealing. I tried two different gaskets, checked to ensure the surfaces of the Quick Fuel carburetor and Toker II manifold are clean, but still no luck. I don't dare tighten the bolts anymore for fear of striping them. Any suggestions?

Man, I see a lot of suggestions being floated about but before jumping to conclusions, I suggest you go back to *basics* and check the mating (mounting) surface for flatness FIRST.

If you don't already have a straight-edge, get one and use it to confirm both surfaces (intake manifold AND carburetor) are true. I have one that's about 12" long that I got from my Snap On man many years ago. I'd bet you can probably find a inexpensive one (the Snap On item is NOT cheap) at Harbor Freight or some likewise company.

It's easy using a straight-edge and a flashlight. If you confirm a gap with a light, use a feeler gauge to see how much of a void you have and go from there.

If both surfaces are true and you still get a change in idle quality or speed, it could be a shaft issue or a open vacuum port you might not be able to see.


Good luck,

Phill

[Tim7139]

On top of checking flatness, do yourself a favor and get a set of four studs with proper nuts, it's a better solution.

[Phill Pollard]

Originally Posted by Tim7139

On top of checking flatness, do yourself a favor and get a set of four studs with proper nuts, it's a better solution.

FYI: I found the carb. stud kits at Pep Boys, cheap to put on my 2x4 set up.


Phill

[cycleguy55]

You might consider one of these gaskets - https://www.summitracing.com/int/par...277g/overview/

They're 1/4" thick and remind me of closed cell neoprene - they'll easily deal with an uneven base, though I'd caution to not tighten them too much.