Choke sticking:
Thread Starter
Instructor
Joined: Jan 2009
Posts: 163
Likes: 1
From: Port Allen Louisiana
Choke sticking:
I have a OEM Rochester quadrajet carburetor. When starting the engine cold, it would idle at a higher idle from the choke. Most of the time in the past after a few minutes it would idle down after warming up a bit. In the more recent past it would not idle down and I would have to give the pedal a hard shot and then it would idle down. Now that doesn't work. It stays at the higher idle as if something is sticking. Would anyone know what I need to adjust for this? I know little about carburetor's other than how to change the fuel filter. lol Thanks for any help...
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
Depending on outside temps the choke needs to be adjusted a little from hot weather to cold. Look on the passages side of the carb and you'll see three little screws holding a black plastics disc in place. Mark where it is with a marker and loosen the screws. There is markings with an arrow on the black plastic that says choke increase or decrease. You want degrease. Only move it about an 1/8 of an inch intervals and try a run cycle. If it needs more, wait until the next morning or a total cold down.
Thread Starter
Instructor
Joined: Jan 2009
Posts: 163
Likes: 1
From: Port Allen Louisiana
Depending on outside temps the choke needs to be adjusted a little from hot weather to cold. Look on the passages side of the carb and you'll see three little screws holding a black plastics disc in place. Mark where it is with a marker and loosen the screws. There is markings with an arrow on the black plastic that says choke increase or decrease. You want degrease. Only move it about an 1/8 of an inch intervals and try a run cycle. If it needs more, wait until the next morning or a total cold down.
Tech Contributor
Joined: Aug 1999
Posts: 14,384
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From: At my Bar drinking and wrenching in Lafayette Colorado
The choke cover has a line scribed on it, and there are notches on the choke housing casting for setup and alignment. If this is an M4M carb (integral choke), your choke cover should be lined up 2 lines to the "lean" side of the centerline (2 notches clockwise). There is no reason to set it at any other setting - if you do, you're simply masking other problems. If the choke does not come off smoothly with the cover set to the noted position, you need to disassemble and clean up your choke components to assure smooth operation. This assumes, of course, that you have verified that your choke pulloff is operational, and that all parts are correctly adjusted as outlined in my Q-Jet paper under the choke setup section. If this is a hot air choke, you need to have the hot air tubes hooked up, and your exhaust crossover needs to be open and operational.
Lars
Lars
Thread Starter
Instructor
Joined: Jan 2009
Posts: 163
Likes: 1
From: Port Allen Louisiana
The choke cover has a line scribed on it, and there are notches on the choke housing casting for setup and alignment. If this is an M4M carb (integral choke), your choke cover should be lined up 2 lines to the "lean" side of the centerline (2 notches clockwise). There is no reason to set it at any other setting - if you do, you're simply masking other problems. If the choke does not come off smoothly with the cover set to the noted position, you need to disassemble and clean up your choke components to assure smooth operation. This assumes, of course, that you have verified that your choke pulloff is operational, and that all parts are correctly adjusted as outlined in my Q-Jet paper under the choke setup section. If this is a hot air choke, you need to have the hot air tubes hooked up, and your exhaust crossover needs to be open and operational.
Lars
Lars
Drifting
Joined: Dec 2012
Posts: 1,360
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From: Meldrim Georgia
Better yet here you go.
https://www.google.com/?gws_rd=ssl#q...+pull+off+test
Tech Contributor
Joined: Aug 1999
Posts: 14,384
Likes: 6,409
From: At my Bar drinking and wrenching in Lafayette Colorado
Put a long vacuum hose on the choke pulloff (remove the short one attaching it to the carb) and suck on it when the engine is cold and the choke is closed. The choke pulloff should retract and pull the choke open 1/4". It should hold your suction and not leak.
Lars
Lars
