2BBL Adjustment... Stalling Problem :(

Discussion in 'Small Block Tech' started by JTY, Dec 17, 2002.

  1. JTY

    JTY 1969 Buick Skylark

    I think the problem is the carb, it's a Rochester 2BBL.

    My car stalls on occasion when I push on the gas, from sitting at idle for a short bit, e.g. waiting at a stop light. It happens when the engine is warm or cold.

    I think it may be the idle RPM on the carb. And, a couple friends agreed.

    Where on the carb would I adjust this?

    Before you ask, I checked the choke, and coil. Also, the carb was professionaly rebuilt a year ago, according to the tag on it. As was the distributor.
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    John,
    Idle speed adjustment on the Rochester 2bbl is on the drivers side. Its a large screw that faces the rear of the carb. Look behind the throttle arm and you will see it. The screw contacts the fast idle cam also. If it stalls on tip in, check the accelerator pump shot. With the engine off, look down the throat of the carb and quickly open the throttle, you should see 2 streams of gas shoot onto the booster venturi. Also check for vacuum leaks at the carb gasket. Get a vacuum gauge on it and spray some penetrating oil around the gasket. When you hit the leak you'll know it. Hope that helps.
     
  3. Smartin

    Smartin Guest

    JTY,

    I had this problem with my 71 LeSabre a couple years ago. I thought it was the carb, so I bought a rebuilt one...same problem. I did away with the 2bbl completely and went with a 4bbl intake and an edelbrock 600cfm 4bbl. I still had the hesitation. I've had a couple speed shops look at it and they both agreed that the problem is loss of compression at low idle. I have a leaky exhaust valve. So, I'm trying currently to find a good set of hads to rebuild and bolt on. Good luck finding a solution to your problem. You might also check timing adjustment and timing chain stretch. You may have to advance the timing very far to get rid of the hesitation, which may indicate the need to replace the timing chain.
     
  4. CyberBuick

    CyberBuick What she used to be....

    Umm.. The original 2GV that came on my '71 had no fast idle adjustment.. I didn't think any of them did. It's a predetermined distance set by the cam when the chokes on.. Stalling at takeoff sounds like a bad accelerator pump or too low a pump shot. The carbs are easy as heck to work on, just don't mix up the two checkballs.. :)

    Do as Larry said and with the engine off, push the throttle all the way open a few times while looking down the venturi. The shot holes are towards the middle from the two venturi boosters. They're aimed to hit the booster itself.

    If it shows nothing, then pop the top off and check the pump. There's two checkballs, a spring and a T that all relate to the accelerator pump system. The checkball in the pump well itself prevents fuel from being pushed back into the bowl. The other checkball is underneath the venturi cluster. It's removable with two screws. Remove it and you should see a metal/brass T sitting in one hole. Needlenose pliars and pull it out. Watch for the spring, it can fly away.. Under the spring is the second check ball. Turn the casting upside down and it 'should' fall out..

    With the venturi cluster removed and that checkball stuff removed. Put the ball back in the accelerator pump well and put some brake cleaner or water in the fuel bowl. Put the pump back in and manually work it down. You should see fluid come up thru the hole under the venturi cluster. No fluid = Pluged hole. Fluid = Something was sticking.

    Have a rebuild kit handy, they're cheap.. Just take some brake cleaner and compressed air and give it a lil bath.. Make sure to do this if you use water as a test medium.

    HTH

    edit: It could also be the float too.. Too low a float level and the accelerator pump won't have anything to work with.
     
  5. JTY

    JTY 1969 Buick Skylark

    I may have a shop take a look at it, while they are doing up my new exhaust system.
     

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