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My 1972 Cutlass 455 has the original Quadrajet carb on it. I had it rebuilt like 20 years ago and re-installed it. The motor has been run very little and starts OK without using the choke and has some run time and maybe 4 to 5 miles on the car since. The car had a manual choke on it and I'm replacing all the manual choke parts. The butterfly moves very little and will not close all the way (maybe 1/4 inch back n forth). I used some Carb/Choke cleaner on it but can get it to move any more. Any ideas??
Once I get the car painted, I may add an electric choke, but paint is my main focus this year.
Have you tried holding the throttle open and moving the choke blade? There appears to be corrosion inside the choke thermostat housing, try to get penetrating oil in the housing on the horizontal shaft that goes into the side of the carburetor. When it binds does the link on the side get bound up or can it be wiggled?
Yes, I moved the throttle and the butterfly released and can be moved to closed or fully open position! I guess I’m manual choke challenged! I will still spray a bit more choke cleaner and then some pens testing oil! Can’t hurt! I does move pretty smooth now!
Thanks for your suggestions and comments! I appreciate your help!
Yes, I moved the throttle and the butterfly released and can be moved to closed or fully open position! I guess I’m manual choke challenged! I will still spray a bit more choke cleaner and then some pens testing oil! Can’t hurt! I does move pretty smooth now!
Thanks for your suggestions and comments! I appreciate your help!
OLE442
In addition to operating the choke plate, the choke mechanism also sets the fast idle cam. If the throttle is fully closed, it isn't possible for the fast idle cam to move. This is why you need to hold the throttle open when pulling on the choke cable. FYI, with the stock automatic choke, pumping the accelerator pedal once before starting both squirts gas in the carb and opens the throttle so the spring in the choke mechanism can close the choke plate and set the fast idle cam.
I may be seeing things in the picture, but it looks as if the choke blade has a 180° bend in just forward of the screws that attach it to the pivot rod. To my knowledge, there isn’t supposed to be any bend in the choke blade. The choke blade is supposed to be flat. Olds may have changed in your year, or I could be way off base. One good step for you is to look up the Rochester carb number on the left rear and compare your carb to known-good carbs. Someone before you may have been engaging in shade-tree tweaks that leave you in a compromised position.
Or maybe I’m seeing things.
No judgment intended, but I’ve found choke mechanisms, electric or heat activated, particularly happy when clean (like really cleaned & polished with #0000 steel wool…) and lubricated. Personally I prefer electric chokes to heat, but, if well maintained, both should work just fine.
Oh - if you switch to electric choke, look up Joe P’s oil pressure before choke wiring tweak and be aware you’ll need to plug a vacuum hole on the choke-to-carb connection front & low plus remove the heat coil gasket so the coil gets a good ground.
I may be seeing things in the picture, but it looks as if the choke blade has a 180° bend in just forward of the screws that attach it to the pivot rod. To my knowledge, there isn’t supposed to be any bend in the choke blade. The choke blade is supposed to be flat. Olds may have changed in your year, or I could be way off base. One good step for you is to look up the Rochester carb number on the left rear and compare your carb to known-good carbs. Someone before you may have been engaging in shade-tree tweaks that leave you in a compromised position.
Or maybe I’m seeing things.
No judgment intended, but I’ve found choke mechanisms, electric or heat activated, particularly happy when clean (like really cleaned & polished with #0000 steel wool…) and lubricated. Personally I prefer electric chokes to heat, but, if well maintained, both should work just fine.
Oh - if you switch to electric choke, look up Joe P’s oil pressure before choke wiring tweak and be aware you’ll need to plug a vacuum hole on the choke-to-carb connection front & low plus remove the heat coil gasket so the coil gets a good ground.
Chris
Chris:
Nope, no bend that I see. I assume that when you say choke blade that you mean the butterfly? Maybe I'm thinking the wrong term.
The car had been drag raced by the original owner in the Houston, Texas area and the carb shop that rebuilt it for me said the butterfly had holes drilled in it so he replaced it. He asked if it had a bigger cam in it and I said no. He said that folks drilled holes in the butterfly when they put in a different cam so it would idle. He also said that there were extra springs and things added to make in "snap open" when you pressed the accelerator. That stuff was all removed.
So, if I'm not seeing what you posted about, let me know of the piece you are questioning. He was well known for his work so I'm sure nothing questionable was put back in. It was done many years ago but I'd doubt it has been driven over 5 miles and stated up and ran a few ours other wise. And yes, eventually I'll switch to an electric choke.
Yes, that is what I call the butterfly but I'm probably wrong. Any rate, it isn't bent IMO and I doubt Frank Johnson would put a bad part in. I finally got the manual choke to work fine, with the info given to me here. It was a pain for a while but not, all is well and it works fine. On to the adjustment of the Hurst Dual Gate cable so I may be posting about that again. LOL! Thank goodness for the Classic Oldsmobile Forum and its experienced members.
Last edited by OLE442; June 20th, 2022 at 12:14 PM.
Reason: spellin'
June 18th, 2022, 05:12 PM
