Rob Peters Posted January 3, 2004 Posted January 3, 2004 My Monte has a Rochester 2brl carburetor and I have torn it down and am rebuilding it. Not sure if anyone here has done this and I have some questions. This may be a long post so I can make my problems understoon. When I tore the carb apart I kept all the old gaskets and parts and took numerous pictures as the disassembly progressed. When I purchased the kit it came with numerous parts including 4 gaskets for throttle body to manifold mounting and each are different, three throttle body to bowl gaskets of which all are just slightly different and numerous parts which my carb doesn't have. I know there are going to be those who feel I should slap a 4brl on her but I want to keep her as close to how she should be. Question 1. I need to determine which is the proper gasket for the throttle body to manifold mounting. I think I have this one figured out. One gasket is about 1/2 inch thick and nothing like the one I removed. Two others are similar and the fourth one has an extra cutout in it. This cutout corresponds with what looks like an exhaust pass through chamber on the lower part of the carb. I suspect the gasket with the cutout is the proper one for mine. Question 2. There are 3 gaskets in the kit for the throttle body to bowl section of the carburetor. Each of these have suttle differences. I have tried to rule two of them out and thought I had it figured out until I looked at the one I took off. This said, I don't think this carb had ever been rebuilt which complicates my decision on which one to use. One of the gaskets has a small hole in each edge of the gasked where it goes around the outer edges of the venturi on each side so I didn't think this would be the proper one. One of the gaskets fit very well and was the one I was going to go with. The third gasket fits similar to the one I was going to go with with the exception of there being two extra large holes or openings (one leading into each large venturi near the vacuum port on the rear of the carb. These holes are so large the opening extends to the outside of the carb in the rear and if I were to use this one it would expose an opening for outside air to enter between the throttle body and the bowl body at the rear of the carb. Like I said, I was ready to use the second one I was talking about until I looked at the old gasket and found it to be exactly like the last one I have described above and would allow outside air into these openings along with any dirt etc. along with the air. Question 3. In looking at the assembled carb, I can't figure out what caused the Choke butterfly to close. I can manually close the choke and the vacuum pull works to open the choke slightly when entergised but I can't figure what forces the choke to the fully closed position. It just seems to move from open to closed freely with nothing to move it into the fully closed position and hold it there during starting. It seems it should be spring loaded to go to the closed positon. Maybe it is something that is on the car up at the garage and I have the carb here at home so I can't compare the two. Question 4. In the power pump area there are two springs. One is on the shaft with the power pump itself and the other one sits down inside the hole where the power pump is. This is not the problem, the problem is this. When I disassembled the carb there was no little bearing down inside this area but the diagram shows one should be there. I am not sure what would hold this little bearing in place other than the above mentioned spring. My question is this, is there supposed to be a little bearing in there and is this spring the only thing that holds it in place. Question 5. The kit came with several extra parts and I know this kit is meant to rebuild numerous different carbs and not all parts are meant to be used. Most of the left over parts are washers, one of them being one that looks like it is meant to be used in an area of heat, sort of like an asbestos washer. Any help anyone can give me would be geeatly appreciated. Even if you can only answer one or two of the questions, someone may know the answer to some of the others. If you have qny questions of me I could email you pictures to make things clearer if you would like. Thanks Rob
Jim Boczar Posted January 3, 2004 Posted January 3, 2004 Rob, I will try to email you the assembly instructions from the 1970 overhaul manual. The check ball is actually not under the power piston but is located in one of the holes next to the bores. It is held in place by a "T" retainer and another spring. The choke stays closed by the rod which goes on the thermostatic coil mounted on the intake manifold. Let me know if you get the email.
Rob Peters Posted January 3, 2004 Author Posted January 3, 2004 Jim, Thanks so much for the information you scanned and emailed me. It was a great help. Mike (Grease) Thanks for your assistance over the phone last night. I look forward to the information you will be sending me. Cbolt, Not sure if I should thank you or not.,....nothing in your post???? Rob
kc8oye Posted January 3, 2004 Posted January 3, 2004 The choke should be pulled closed by the thermostatic coil inside the choke housing it's possible if its warm hwere you are working on the carb, the choke may not close wish I could help more rob, I've never messed with the 2bbl rochesters. my qjet kit only came with two gaskets for the airhorn and tb gaskets, and they were easily distinguishable ;( Haynes has a good book on rochesters.. check your local parts store. if I had inet at home, I'd bust teh book out and help ya
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