When we rebuilt original MC2150, there is an unavailable part inside the altitude compensator, and said to be essential for proper function of the carb.
20231111_084004 by
Scott Weckerly, on Flickr
Access to where the silicon seal fits is under the spring cage. Gently grasp the cage, wobble back and forth slightly, it comes off easily to remove the valve.
20231111_083949 by
Scott Weckerly, on Flickr
The center here is where the silicon seal goes as the mounting area is slightly collered so it seals around the housing.
20231111_083531 by
Scott Weckerly, on Flickr
The valve simply lays horizontal in place held by the very low tension spring against the cage.
20231111_083607 by
Scott Weckerly, on Flickr
Little silicon seal that goes in around the shaft of the compensator valve stem was torn, so I set it aside to research another or repair ideas where it would not get lost......forgot where I put it when we did the rebuild....DOH! So put the carb back together without it, to see if it was really needed.
So carb works without it, and the next day Mongo228's eagle eye found my misplaced part.......on the bench right next to my tool box.....right where I had put it but hiding behind a roll of tape!
As the repair method calls for RTV to bond the torn silicon back to form, Mongo228 repaired the part, and we set it aside to cure.
20231111_083632 by
Scott Weckerly, on Flickr
Yesterday I pulled the compensator off the carb, and installed the repaired silicon seal.
20231111_083744 by
Scott Weckerly, on Flickr
The altitude compensator comes from the factory preset, and instructions say to NOT adjust this set screw. We did use some carb cleaner through this device, and put an allen wrench in to turn back and forth for cleaning, and the spring inside is a very strong coil. I did mark where it was originally set, so we could leave it like we found it.
20231111_084019 by
Scott Weckerly, on Flickr
So....carb rebuilt, adjusted, settings where they should be, drives out and performs better than the chicom knock off Mongo228 gave me to use when truck was initially in get running stages. But....does not pop off cold start as good, warm idle not as smooth. Not happy with that part of it, so need to tinker some and see if it will smooth out. Eventually replacing with 4 bbl, so gladly work with this one until then.
'81 CJ5 Base, 258 I6, MC2100, T176 4 spd, 300 TC, D30 Front NT, 3.31, 2-Piece AMC 20 rear NT, 3.31, 4" high arc spring lift
'84 Grand Wagoneer, 401 V8 (.030 over), Edelbrock clone 1406, 727 auto, Selec-trac NP229, AMC 20 REAR - D44 FRONT - WT 3.31, 4" high arc spring lift
Rather be driving, than waiting to be modified