The Stovebolt Site Forums The Shop Area General Truck Talk Fix crossthreaded fuel line fitting on carburetor?

Folks,

I rebuilt my carburetor this past weekend and noticed that the fuel line fitting thread inside the carburetor was cross threaded. I thought that using teflon would stop a leak from occuring, but unfortunately, I noticed that there is a slow leak dripping out.

The carb is an old rochester 4jet with what looks like a 3/4" fuel fitting line.

Here are some pics of the carb pre-rebuild:
http://homepage.mac.com/spider/truck/carb/carb.html

Any ideas on how to stop the leak or fix the thread?

The type of repair depends on the type of thread.

For a straight thread (with a gasket seal), install a helicoil of the proper thread.

For a tapered (pipe) thread, tap to a larger size, and fabricate an insert plug with a flange and a gasket. Tap the insert for the pipe thread. Install the insert with a couple of drops of red loctite on the insert threads. Let set for 24 hours and then install the original fitting in the insert.

I used to make the comment that only plumbers would use teflon, until my father (who has done a LOT of plumbing) informed me that no competent plumber would ever consider the stuff.

The only really GOOD use for teflon tape is to put on stakes you put by newly planted trees. The teflon tape flutters in the breeze, and the individual using the lawnmower does not mow down the trees! (MOO)

Jon.

I have had luck with this method.
Try starting the fitting backwards and keeping it as straight as possible. At some point you will feel it kind of like catch a tread. Then when you feel that try to screw it in, if you get lucky it will catch one of the original threads and start straight.

Good luck,
Wilbur

Wilbur,

I tried that initially and thought it would work, but the thread is pretty much gone now.

Jon, it is a straight thread with gasket seal, so I'll try finding the helicoil, but most of the local parts stores don't have anything bigger than 1/2".

Teflon does have its uses and have had some luck in other situations. I like your teflon garden decorating idea too; didn't think of that before!

I think Summit and some other hot rod outfits sell a repair fitting just for that. It cuts its own threads and is a little oversized to get a good fit. I can't promise they have it for a 4-jet,but I've bought 'em for Hollleys before,so there's a good chance they have 'em for others..
Speed

Thanks for all the advice. I haven't been able to locate the right helicoil around here, so I'll keep checking.

In the meantime, I used a ugly but effective solution: liquid teflon. By the time it cured, it looks like the leak is gone. That's enough to get me thru the next couple of weeks.

jb weld a nipple in then use rubber fule line worked good on my boat

Most part stores make a self threading coupler that will screw into the filter housing and clean the threads as you install it. I would suggest that you do not install the filter and install and inline filter, that way you will never have to remove the housing again. The self taping couplers sometimes wont seal the second time you remove them.

Uh??? Did you install the sealing ring on the housing?

Agree with 32-Fire. It's hard to beat that good ol' gas-proof J-B Weld.

Guys,

Thanks for all the input.

Toyvo, yes, the sealing ring is there; the thread is definitely stripped.

Given the lack of decent parts stores around here, I may have to go with the JB weld route.