rough start

Old Apr 10, 2011 | 09:16 AM
  #1  
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rough start

so i been having starting problems first thing in the morning when the engine is cold. i have to hold the gas so it wont turn off. once warm it runs better. sometimes once engine is warm and i put on drive it feels like it wants to shut off. i have a 350 4bb q-jet
Old Apr 10, 2011 | 10:59 AM
  #2  
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Originally Posted by al714
so i been having starting problems first thing in the morning when the engine is cold. i have to hold the gas so it wont turn off. once warm it runs better. sometimes once engine is warm and i put on drive it feels like it wants to shut off. i have a 350 4bb q-jet
Al your two problems are likely related. Did this problem start when your "mechanic" rebuilt your carb. If he disconnected your vacuum advance when he worked on your distributor, he probably disconnected your choke when working on your carb.

https://classicoldsmobile.com/forums...m-advance.html
Old Apr 10, 2011 | 11:50 AM
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i read on the manual on how to adjust the choke coil.It says to place cam on highest step and rotate cover counterclockwise until choke closes. i put the cam on the high step by adjusting the fast idle screw on it.but i noticed that the choke dosent open after engine is warm.sounds like the choke is bad maybe? also cam didnt go down cause of the fast idle screw lever was holding it . i know im doing something wrong what is it. please someone help.also pulled on throttle so it can release the cam. but have to pull twice so it can move.

Last edited by al714; Apr 10, 2011 at 05:02 PM.
Old Apr 10, 2011 | 09:36 PM
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Pull the fast idle cam all the way up. Adjust the fast idle screw until the car runs about 1200 rpm. Shut it down and let it cool. Now put the fast idle cam up all the way again and adjust the black choke cover until it moves the choke blade until it is closed. Just enough to close, not to tight. Now run again and let it warm a couple of minutes and the it should kick down some and when warm, it should idle down to normal rpm. You may have to do some fine tuning on it. Good luck.
Gene
Old Apr 11, 2011 | 04:28 AM
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Does the choke open up slightly just after start up? Check the choke pull off, choke should open about an eighth inch immediately after start up. Pull off works off vacuum from carb. Make sure hose is connected to the proper port. If diaphragm is getting vacuum but does not open choke then the diaphragm is most likely bad.
Old Apr 24, 2011 | 07:21 PM
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ok i i did everything that was suggested to me the choke pull off must be bad cause it dosent move once car is started, so ill get a new one.i also decided to check timing. it was off so i adjusted it at 12btdc at 1100 by adjusting the the fast idle screw. but i noticed that the engine seemed like it was going too fast .also the fast idle cam would get stuck with the cam thats conected to the fast idle cam screw everytime i pressed on the gas. am i doing this right? also when i tighten the bolt that holds down the distributor the car didnt want to start.its been loose since a mechanic supposably fixed it. can somebody please help me help on how to do this right so i can do it.. dont trust no mechanic on my car.oh yeah he said my chain was problably loose or that it skipped a tooth. i took out the gas pump to check the chain and it was super tight.
Old Apr 24, 2011 | 07:41 PM
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It is very hard to troubleshoot an engine over the interwebs.

There are a lot of things that could be wrong, and the real problem is that none of us here knows what you don't know, so it's very difficult for us to calibrate our responses.

There are a lot of parts involved in the proper operation of the choke, and it is impossible for us to be able to fully rely on your written descriptions of what you have observed for a complete picture. A careful, detailed video of the carb during starting and running might be helpful, but it also might not.

I would strongly recommend reading the section in the Chassis Service Manual that describes carburetor operation, adjustment, and troubleshooting, as well as the section on adjusting the points and the timing, and possibly also the Rochester QuadraJet Manual, then going back and observing the carb again, then asking new questions here.

I personally do not think I know enough about what's going on with your car at this point to offer any adjustment advice at all, and I don't want to tell you the "wrong" thing and have you break something.

- Eric
Old Apr 25, 2011 | 03:47 AM
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The old manuals can be very useful. Some have some very good diagrams and trouble shooting proceedures. They are also interesting reading.
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