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Tue Apr 11, 2017 7:34 pm

Hi,

I just rebuilt my H30/31 Pic carburetor for my '67 bug and see that it's slow leaking a small amount of fuel in the top gasket and on the bottom gasket. Nothing so much that it will catch fire, but I can run my finger around the gasket and pick up fuel on my fingers. The rebuild kit came with those grey paper gaskets. I was wondering what people use or recommend for sealing those gaskets? I think I read in Muir's book to put some oil on the gaskets for a better seal, at least on the valve cover gaskets. Is this recommended for carburetor or other gaskets? What about wheel bearing grease? I don't want to use those gasket sealers that are ultimately impossible to remove.

Thanks,
Joseph

Tue Apr 11, 2017 8:35 pm

Try Permatex Aviation, a THIN film on both sides of the gasket and metal surfaces. That's the brown goo.

Do NOT use RTV - that's not resistant to gasoline !

Tue Apr 11, 2017 9:48 pm

When you rebuilt it, did you remove any inserts protruding on the mating faces, then plane them flat (using every cloth taped to a plate of glass, for example)?

Years of prior owners over-tightening the screws leaves the castings distorted at the faces, and this will fix that. Then you can install the gaskets dry and not have any leaks.

Tue Apr 11, 2017 10:06 pm

I've always smeared a very light coating of grease on the paper type gaskets. Just enough to make them wet. However if the surfaces are not clean and flat, you're not going to get a good seal regardless.

Wed Apr 12, 2017 1:35 am

I just make sure both surfaces are flat and install them clean and dry... I even do the same for sump plates.

Wed Apr 12, 2017 6:37 am

anthracitedub wrote: I just make sure both surfaces are flat and install them clean and dry... I even do the same for sump plates.

Same here. Flat, clean and dry.

Wed Apr 12, 2017 1:58 pm

Pruneman99 wrote: . . . if the surfaces are not clean and flat, you're not going to get a good seal regardless. TRUE!

The carburetor rebuild gaskets get NO sealant!!!!

FWIW, your carburetor gaskets should never have any type of sealant applied to them!

And BTW . . . do NOT use any sealant on the gaskets when reassembling the carburetor! :wink:

Pruneman99 wrote: I've always smeared a very light coating of grease on the paper type gaskets. Just enough to make them wet.
I always do this for the manifold-to-cylinder head gaskets and also for the carburetor-to-manifold gasket(s).

Wed Apr 12, 2017 2:57 pm

Weber carb installation instructions detail to use sealant such as Permatex aviation on the gaskets.

Wed Apr 12, 2017 3:59 pm

The tech tips section on Aircooled.net says to use Chap Stik. Sounds like a neat idea to keep them from sticking, but I wouldn't try to stop a leak with it or put it on a gas soaked old gasket.

Wed Apr 12, 2017 4:04 pm

Cusser wrote: Weber carb installation instructions detail to use sealant such as Permatex aviation on the gaskets.
Sorry Cusser . . . I missed that :oops: . . . where can I have a look at it?

I have seen these bits of info . . .
https://www.thesamba.com/vw/forum/viewtopic.php?t=604066&highlight=carb+sealer
http://cbperformance.net/pdf/WeberInstallationGuide.pdf
http://cbperformance.net/pdf/WeberICT.pdf

Wed Apr 12, 2017 4:49 pm

I used to install dry, but Evey once in awhile I would get a small leak/weep. Since applying a VERY THIN COAT of grease, I can't remember the last time I had a leak that was not caused by some sort of deformation. Maybe the grease just helps the gasket to slide just a bit so it won't pinch. IDK for sure, but it works for me.

I don't like sealers, as they have caused me more leaks than the dry method. Well each their own, more than one way to do it. Whatever your comfortable with and works for you.

Wed Apr 12, 2017 7:15 pm

57BLITZ wrote: Cusser wrote: Weber carb installation instructions detail to use sealant such as Permatex aviation on the gaskets.
Sorry Cusser . . . I missed that :oops: . . . where can I have a look at it?

That information was included in the instructions with the Weber 32/36 DGEV kit for my 1988 Mazda truck; I don't have that electronically (like PDF) though.

When I installed the single Weber 40DCNF to its dual port manifold for my VW in 1976, can't remember if I used sealant or not, and I have not removed that carburetor in all these years, still runs fine on my 1835cc engine (but I did replace the accelerator pump diaphragm once).