FIXED - AFB 4bbl broken adjustment screw
Well I got brave or stupid and decided to try drilling out the adjuster.
Started out with a 1/16" down the center of the shaft, VERY VERY SLOW, so far so good, got down about 1/8" or so. Stepped it up to 3/32" and enlarged and lengthened the hole.
The dang adjuster started to rotate into the bore until it got past the threads. Now it is sitting slightly sideways and the tapered pin part can be seen from the bottom in the venturi.
I looked into the other bore and saw that the large plugged hole next to the adjuster makes a cavity large enough to remove the remains of the adjuster. So I drilled out the lead plug and luckily it can out in one piece except for the hole in the center I drilled. I thought about trying to pry it out but figured I would do more damage to things.
So after some additional drilling to make the remaining threaded part of the adjuster smaller it came out.
I thought the threads in the adjuster hole were stripped out but it turns out that they were just dirty. I will run a tap through and see how the existing adjuster fits. It does not look like there is any other damage so now I can start to rebuild it.
Some things I might have done differently:
1. I would use left hand drills (in my case it would not have come out as someone had screwed the set screw hard into the adjuster threads and messed them up good. If it had come out I would have had to helicoil for sure)
2. A drill press (to keep things parallel, centered and aligned)
3. drill the smallest hole as deep as possible (when i went to the next larger size bit, turns out my pilot hole was a tad off center and it caused the larger bit to walk out the side)
4. drill dead center on the adjuster (see above)
5. A 1/16" bit fit into the hole from the venturi side and could have helped keep the adjuster in place while drilling
6. Might have tried to use the set screw to hold the adjuster from rotating if I only had right hand drills
In the last photo the damage to the threads is the damage done by the set screw
All in all a good outcome.
I still want to try the ALUM method , I even bought some from the grocery store. I saw a different you tube video that looked like it would work
Well I got brave or stupid and decided to try drilling out the adjuster.
Started out with a 1/16" down the center of the shaft, VERY VERY SLOW, so far so good, got down about 1/8" or so. Stepped it up to 3/32" and enlarged and lengthened the hole.
The dang adjuster started to rotate into the bore until it got past the threads. Now it is sitting slightly sideways and the tapered pin part can be seen from the bottom in the venturi.
I looked into the other bore and saw that the large plugged hole next to the adjuster makes a cavity large enough to remove the remains of the adjuster. So I drilled out the lead plug and luckily it can out in one piece except for the hole in the center I drilled. I thought about trying to pry it out but figured I would do more damage to things.
So after some additional drilling to make the remaining threaded part of the adjuster smaller it came out.
I thought the threads in the adjuster hole were stripped out but it turns out that they were just dirty. I will run a tap through and see how the existing adjuster fits. It does not look like there is any other damage so now I can start to rebuild it.
Some things I might have done differently:
1. I would use left hand drills (in my case it would not have come out as someone had screwed the set screw hard into the adjuster threads and messed them up good. If it had come out I would have had to helicoil for sure)
2. A drill press (to keep things parallel, centered and aligned)
3. drill the smallest hole as deep as possible (when i went to the next larger size bit, turns out my pilot hole was a tad off center and it caused the larger bit to walk out the side)
4. drill dead center on the adjuster (see above)
5. A 1/16" bit fit into the hole from the venturi side and could have helped keep the adjuster in place while drilling
6. Might have tried to use the set screw to hold the adjuster from rotating if I only had right hand drills
In the last photo the damage to the threads is the damage done by the set screw
All in all a good outcome.
I still want to try the ALUM method , I even bought some from the grocery store. I saw a different you tube video that looked like it would work