The Stovebolt Site Forums The Shop Area Engine Shop Gas Leak at the fuel inlet on the carb

1 bbl Rochestor carb. I have a fuel leak where the fuel line enters the carb. I have tried a small brass nipple and a brass MPT to barb fitting. Both of them leak. So the question is, is there anyway to seal this junction? Is there a pipe dope for gasoline or Thread tape. I know that there are possible issues with the sealant or tape fouling up the carb. I would still be interested in any possible solutions.

Thanks

I would try Loctite 592. Do not use teflon tape. Slivers will get in your needle and seat.

I use Permatex Seal Lock. It's a combination thread sealer and blue thread locker

I have the teflon tape that’s designed to work with gas, it’s kind of pink and thicker than the white.

I'm confused. On my carb, (Rochester B) the fuel line is flared and you just have to tighten the flare nut. The other side of the adapter threads into the carb body; I have copper washer there to stop leaks.

No tape or pipe dope required anywhere.

The threads on his carb might be worn out/stripped or something.

The thread going into my Carb is 1/8 NPT.

Probable causes:

(1) threads in carburetor housing are now worn TOO DEEP, due to overzealous previous owner overtightening of the fitting OR the use of one of the forms of Teflon.
(2) the carburetor casting is cracked at the fuel inlet, due to a previous owner using some form of sealant/lubricant (Teflon is a wonderful lubricant).

Possible solutions (if you are dealing with a 1949 truck as indicated in your signature block):

(1) Remove the aftermarket Rochester B and install an original Carter type W-1 carburetor.
(2) Remove the aftermarket Rochester B and install an aftermarket Carter YF.
(3) Replace the air horn on the Rochester B with a new old stock or good used one.
(4) Machine a new brass fitting with slightly oversize threads. This fix will work for (1) but not (2) of the causes. This fix normally reserved for use with EXPENSIVE carburetors.

Jon

I second this, a copper "crush" washer seams to do the trick.

Some of the "B"'s have pipe thread (tapered) into the carburetor casting, others have a uniform diameter thread, and a gasket.

Jon

Here's another idea that might work for you...Fixing threads

Although JB Weld is resistant to gas, it is not resistant to alcohol.
If you use gas mixed with ethanol, the long term effects are debatable and not really known.

While JB weld is good for many things I am not going to do that on a carb.

JB Weld Tank Weld is ethanol tolerant and can be used to patch holes in fuel tanks.

I wouldn't use it for thread repair, though since the vibration might break it loose and cause an underhood fuel leak.

carbking Jon has your answer. Pitch your fire starter Rochester model B and find the correct W1 Carter that belongs on your '49.

If you HAVE to keep the Rochester and it has pipe threads you could try a helicoil style insert LINK.
Full disclosure, I have not tried an NPT insert, but have used helicoils on straight threads a number of times.

I was thinking about a Helicoil too. Didn't know they were available in NPT, make sense though.

If you go with a helicoil, use a liquid thread sealer, you now have twice the threads to seal, the original size and now the added helicoil size.

I`d try this first. Let it cure a couple days

What is the casting number on the air horn casting ?

Jon

Still waiting on the 592 to come in. I will let you all know what the results are once I do.

What's the 592?

Another "miracle in a tube" !

Jon

Jon not sure I have seen a casting number on the air horn. Where should I look for one?

Brian - I'm not Jon "carbking", but I can offer some current pictures from what I know to the best of my knowledge is a 1953-58 Chevy 235 truck Rochester B that you can take a look at and try to figure out what you have.

My info on this being a '53-'58 truck 235 carb comes from this Rochester B Identification thread put together by Jon "carbking" and "John Milliman" (the Big Kahuna) to help Bolters figure out what they have. The PDF files attached to this thread must be downloaded to read as they won't open for some squirrely reason.

Hope this may help.

Picture