Carb Rebuild Problem

[jwr0001]

I have an Autolite 4100 4B carb. The main and secondary butterflies are really stuck! I soaked them in carb cleaner overnight. They are still frozen!! I do not want to tear anything up.. Does anyone have any ideas?

[Phillyfanfrombirth]

Sounds like they are rusted into position... Plenty of WD 40, and patience might get it unstuck... but even then, I'm not sure how good it will get...

[Gearhead999]

PB Blaster is a better penetrate than WD-40. Or soak it in ATF. After soaking some, try and work the shafts back and forth. If that doesn't work. Remove the butterflies and knock the shafts out.

Make sure that you mark the butterflies before removing them. Also, you have to file/grind the peening over of the butterflies screws to make the removal. Make sure you peen them over after reinstalling [ask me how I know !!!].

[jwr0001]

Thanks for information. I will try PB Blaster and/or ATF. I had the butterfly screws out yesterday but was afraid to use force to knock out butterflies or shafts.

I did not peen the screws prior to reinstalling yesterday. Please tell me why this is neccessary? However, two of the screws were very difficult to reinstall.

Have you ever seen a carburator actually work properly after removing/cleaning/reinstalling shafts and butterflies? Please tell me "Yes"...

[Gearhead999]

You peen the screws so they will not fall out and become ingested by the engine. When you peen them you use a center punch, but make certain that you support the shaft from the oposite side so you don't bend the shaft. Lock-tite is a good idea too. I'd use "blue". So you can take it apart, if necessary.

Yes, I've seen many carbs run fine after all that removal and reinstall.

Also, as I said earlier. Mark where the plates go before you remove them. When you put them back in the bores and through the shafts, you should leave the screws slightly loose so you can fit the throttle plates to the bores so they are centered and don't stick to the bores. Hold them up to the light and see the light around the edges to help in centering them.

Lastly.....don't use "Force" on anything in the carb. You'll have trouble later for sure. Let them soak for some time, like overnight.

Take care...
Merry Christmas !!!!!