Carb fuel inlet thread repair

W

w30bob

Well-known member
Hi Guys,

I've got a couple carb top halves that are in good shape except for bunged-up inlet fitting threads. I don't think there's enough meat in the casting to drill and tap for a heli-coil, but I'm sure you guys know for sure. Has anyone successfully repaired those inlet threads? I know the repop carbs are cheap, but I'd hate to toss out original parts if they can be saved.

Thanks,
Bob
 
There is an Edelmann fitting that is 1/4" male pipe thread by 5/16" compression fitting. The pipe thread end can be JB Welded into the inlet and then the compression end used on the fuel line. The ferrule will need to be cut off and the line shortened a little bit. You can't remove the screen once this has been done, but it can be cleaned with carb cleaner and back flushed by removing the needle seat. As Barnyard said, check to see if you can helicoil first. If you have the correct size drill bit for a 1/2" x 20 helicoil, you can insert it and see how sloppy a fit there is. Sometimes there is not enough metal at the top to cut good threads and the helicoil will not thread in. If you need the Edelmann part #, I can get it tomorrow.
 
The few I have done were easy. I drilled a few holes in a 2X4 to mount the carb square, clamped on a drill press table, set a depth to keep from drilling into the seat and then used the drill press to steady and hand tap the hole. I do not have the Helicoil sized drill bit but drilled to the next smallest size I had. If you have the correct size then certainly use it but the metal is soft enough it works well with the next smallest size common bit.

The Helicoil will likely be too long so I trim the length prior to insertion with a Dremel style grinder and a small cut off wheel. I use Locktite on the Helicoil and wait until the next day to break off the tab.

Straight forward process.
 
Hi Guys,

Well THANKS. I feel much better about trying to fix my threads. I'm glad I didn't toss those carb tops out.

regards,
bob
 
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