Carb Rebuild Problems

[FL-Rider]

When drilling in a carburetor, there is very little room to drill off center or enlarge the hole. The carb body around the screw could be very thin and have another chamber of the carb right next to the screw hole. At this point, see if the screw head shape is the same as the original screw. As long as it contacts the needle seat bracket the same way, it might work. For example, if the original has a flat surface under the head, make sure the new one does too. I forgot which type it is off the top of my head. Something else that may have happened too is that during the drilling and enlargement process, the screw hole may have come very close to the hole where the needle seat sits in. Maybe the screw is causing a bulge in the carb body wall between the seat hole and the screw hole and is causing the seat to rise up? Just a thought.
Try putting the seat in without the screw and bracket. If it goes all the way in, then put in the lever arm, spring, lever arm rod, and lever arm screw. Then operate the lever arm with your finger and see if it lifts up the needle and then springs shut again when you let go. If all that checks out, then its got to be a problem with that screw for the needle seat.
If nothing else works, jb weld might be your only choice.
Question: were you able to get all of the old screw out?

 

[FL-Rider]

I think there is a epoxy product that you put in the hole and insert the screw with a nonstick coating while its wet. It cures around the screw and creates the thread that way.

 

[f15radar]

When drilling in a carburetor, there is very little room to drill off center or enlarge the hole. The carb body around the screw could be very thin and have another chamber of the carb right next to the screw hole. At this point, see if the screw head shape is the same as the original screw. As long as it contacts the needle seat bracket the same way, it might work. For example, if the original has a flat surface under the head, make sure the new one does too. I forgot which type it is off the top of my head. Something else that may have happened too is that during the drilling and enlargement process, the screw hole may have come very close to the hole where the needle seat sits in. Maybe the screw is causing a bulge in the carb body wall between the seat hole and the screw hole and is causing the seat to rise up? Just a thought.
Try putting the seat in without the screw and bracket. If it goes all the way in, then put in the lever arm, spring, lever arm rod, and lever arm screw. Then operate the lever arm with your finger and see if it lifts up the needle and then springs shut again when you let go. If all that checks out, then its got to be a problem with that screw for the needle seat.
If nothing else works, jb weld might be your only choice.
Question: were you able to get all of the old screw out?

I am not sure I got the whole screw out. I thought so based on the depth of the original screw. I can put everything in without the retaining ring and it works but obviously it doesn't pop because the seat starts leaking. Any idea what the epoxy product is called?

 

[FL-Rider]

Loctite - Form-a-thread

 

[etemplet]

I got at pile of carb bodies. Might have something you can use. I"ve never had any luck with form-a-thread or anything like it much less in a hydrocarbon environment.

 

[POPPS]

I would find a replacement carb, making sure all the threads are normal.

 

[FL-Rider]

There are also minature helicoils in M3 that could possibly work. No guarantees though.