I have the original 70241102GV not the 2GC on my car's engine. (see below)
The basic 2G design remained unchanged throughout its production run. The main distinguishing features are a power valve in the bottom of the float bowl, and a side hung float with the needle and seat inverted in the airhorn. The power valve is the same as used in the 4G four barrel and the accelerator pump is a similar design. Early 2GC carburetor
The 2GC is the automatic choke version with the choke coil mounted on the side of the carburetor. In early versions (1955 - late 60's) the choke thermostat assembly is attached to the airhorn (top part) of the carburetor.
The choke coil is heated by hot air drawn through a tube connected to the intake manifold at the exhaust crossover or the exhaust manifold.
This layout was used in marine applications into the late 1980's. In many cases, the hot air choke was replaced with an electric choke coil.
Pontiac 2GC
Starting in the late 1960's the choke thermostat moved down to the throttle body. This arrangement was used until the last domestic automotive application in 1979.
Chevrolet 2GV Carburetor
Another choke arrangement, used mainly on Chevrolet engines was the 2GV, in which the 'V' referred to the choke coil being remotely mounted on the manifold.
Carburetor Size and CFM
Rochester 2G carburetors came in two basic groups: big and small.
The small 2-Jets were used until the early 70`s, where they last appeared on 307 Chevy engines.
Large 2-Jets, with a bigger bolt pattern, started in the late 60`s on BOP engines. By 1973, all automotive 2G`s used the large flange.
Some classes of stock car racing need large Rochester 2-Jet carbs. These can be found on early 70`s Chevy engines, including governed big-block motors in school buses. The school bus carbs require modification to the throttle body assembly to be usable.
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Prince Edward Island
'64 Parisienne CS "barn find" - last on the road in '86 ... Owner Protection Plan booklet, original paint, original near-mint aqua interior, original aqua GM floor mats, original 283, factory posi, and original rust.
sooo.. i put the manual choke on and put it wide open, but when i press the gas, the idle cam drops and i have no idle so it stalls out. Is there supposed to be some sort of spring in the choke piston? I dont see one in any diagrams though. Is the arm supposed to be bent a certian way? Its just weird that it worked a month ago, but not now. i dont think i changed anything?
These are actual scan from the 1961 Pontiac shop manual (series 7000 Canadian) The manual has all the adjustments of your carb. I hope this helps. Maybe someone who can spot the related problem in the following pages can advise you as to which adjustment to make.
ya, I read that after i wrote that post! LOL!! I took the electric choke off my quaddrajet carb and it fits on the roch. carb. On sunday hopefully i can get some garage time and try it out.
i was fooling around with the manual choke and almost have it right, but it just wasent sounding right. So im thinking, is it running on all cylinders? I put my hands on the header tubes and a couple of them are cool, while the other ones are hot!! HMMMM! So I pull out the plugs (after I checked for spark, and i also grabbed the plastic handled screwdriver instead of the rubber one..OUCH!! LOL!!) and they were a little dirty so i just quickly cleaned them, put them back in and presto!!! Car runs fine. I think over the winter as i started it now and again it just got some carbon buildup and thats why i was having such a hard time. Im learning so much with this car and your guys help, thx!!
I had a carb similar to this on a small block years ago, and I had choke grief as well. I do not know if it was the identical carb or not, but I wound the choke so the butterfly would stay open, and the fast idle cam you talk about I zip ied it down so didn't engage at all. Now the upside to this is I never had anymore problems with the carb.....the downside was I had no choke at all!!! And in the winter you could not leave the car by itself to warm up, it was a foot feed to keep it running for about ten minutes til it warmed up then it worked fine!!!
By the way, I love the look and stance of your car......very cool!!!!!!!!!!
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John
1972 Pontiac Lemans (daughter's car) 2005 Pontiac Grand Am 2004 Ford Explorer Sport Trac
i was thinking about some crazy glue soon!!LOL Thanks for the kind words about the car, its sitting on cut springs and if you see alot of rat rods they have the same look to them, and it doesent cost alot. I would love to restore it back to original, but it costs too much and i really dont think that would be me.
yeah, I geuss you really have to think about it in a simple way, its usually something really easy to fix. I did have a good day yesterday with the car as i first got it running better, then i had no brakes and saw that it was leaking where i put the new front flex hoses on, so i fixed that. Then i was trying to fix the gas gauge and figured out the break was in the trunk, so that was an easy fix, and then made its home(garage) a little nicer with a new wall and cleaned it up a bit. Oh, and after that I wired up my neighbors garage with a motion light and a new light out front and I did it right the first time!! That usually doesent happen with me!!