Throttle shaft bushings in Autolite 2100?

[Nothing Special]

The throttle shaft bearings in my carb are a little sloppy and the idle speed changes significantly when I spray carb cleaner at the throttle shaft. So I was thinking I'd "just" ream it out and press bushings in. But, as usual, the word "just" doesn't really mean what you'd think it means.

The issue I'm running into is that the wall outside of the throttle shaft bearing is only about 0.100" thick. I found this kit that includes a 10.9 mm (0.429") reamer to press in 11 mm (.433") OD bushings. But that only leaves about 0.070" of aluminum outside of the bushings. That seems pretty thin to me. Is there a better way to go with this?

 

[tirewater]

I bought the one from 'carbjunkys' looks to be the same:

https://www.ebay.com/itm/232134063156

Given the bushing replaces the worn carb wall, I wouldn't worry about the thinness of the aluminum wall too much. Just be careful when reaming.

I don't remember if instructions came with the kit, but the smooth end of the reamer goes into the throttle rod journal and you attach a drill to the flutes. This keeps the ream centered (as much as can be).

This is a stop gap solution, a machinist or drill press with a fixture would give you a higher likelihood of a centered hole.

I was more worried about removing/installing the butterfly valves. Making sure they're centered and allow for the throttle to open/close smoothly. I ended up using red loctite with a screw + lock washer to install them.

All in all, the repair seemed fine. However it would be better to find a carb body with a decent throttle.

 

[jckkys]

The reamer is guided by a pilot shaft so it should be fine. I understand your concern, but haven't read of anyone who cracked the wall. Cutting oil and repeated pull backs to clear chips that could load up the flutes are how I would begin. The procedure for reinstalling the throttle plates is fairly simple. I've done it dozens of times, mostly on used carbs that some knuckle head had screwed up. Some times I do it to install a shaft with the kick down lever. I only buy used carbs. So get plenty of practice fixing problems. The throttle shaft bore wall thickness isn't an issue once the reamer cut is done and the bushings are pressed in.

 

[Nothing Special]

OK, I'm convinced. The kit's on order. Says it won't be here until Sunday, so I don't know when I'll be trying it.

 

[Nothing Special]

I got the kit. I was able to make it work, but I'm not impressed with it.

First off, yes the reamer shank was the right diameter to pilot in the throttle shaft bushings. But it wasn't long enough to get a drill on after you stuck it through. In fact it didn't stick out of the other side of the carb at all.

So I chucked it in my drill and spun it while hitting the front end of the reamer with a grinding wheel. This turned the front end down so I could grab that with the drill chuck and use the shank for the pilot. Problem solved.

Next thing was that it wouldn't cut. At all. Even the soft aluminum of the carb body. Turns out the back edge wasn't sharpened. So I took a small grinding wheel on a Dremel and sharpened the back end. I didn't do a great job, but it was good enough to cut the aluminum. Problem solved.

But then the 11 mm OD bushings were a free slip fit into the 10.9 mm holes. So the reamer was cutting oversize. Some epoxy on the OD of the bushings fixed that. So final problem solved.

It's together now. The throttle shaft moves freely through its entire travel. I started the engine and there's no change in idle when I spray carb cleaner at the ends of the throttle shaft. So as I said, it all worked out, but I'm not impressed with that kit.

 

[gnpenning]

While it was mentioned that both kits look the same.

Specifically which kit did you buy??

 

[Nothing Special]

The one in the link in my first post

 

[gnpenning]

Thanks..