Ok so I have a 1961 bel air 283 2 barrel Rochester that I have been working on for 2 weeks solid trying to pinpoint why it won’t idle in gear without feeling like it’s on 4 cylinders. I have uploaded videos of it idling in park where it idles wonderfully and revs perfect. It seems to drop about 300 rpm and just tries to die in gear. Car has new distributor cap, new coil, new points, vacuum advance plus hose. New plugs, new gas tank, carburetor was cleaned and new gaskets installed. It holds 15 pounds of vacuum at idle. Timing seems to be way off as shown in video. But at 4 degrees btdc it runs very rough. Also the carburetor seems to be giving gas at idle from one bore only. I have checked for vacuum leaks with starting fluid and can’t find any. Any ideas?https://youtube.com/shorts/eiAIsAZPfq8?feature=sharehttps://youtube.com/shorts/KNqgmqrG5IQ?feature=share https://youtube.com/shorts/KNqgmqrG5IQ?feature=share https://youtube.com/shorts/QcHFTIDVOlo?feature=share
Only have fuel on one bore? then it’s stopped up somewhere. I’ll turn the idle mixture screws in one at a time. If it tries to stall or starts to run rough, then that’s usually clear. If it’s running rough and adjusting the idle screw in doesn’t change anything then it could have some kind of obstruction Check for vacuum leaks. I had a carb act goofy and found an issue with a leak between the body of the carb and base. my 350 started idling on what sounded like 4 cylinders. One side idle circuit would not change when screwed in. The other side would stall the engine. Removed the idle mixture screw on the side that didn’t change, blew it out with compressed air. Ran much better after that
Finally figured it out, one of the tiny idle tubes had a tiny particle of rust blocking it half way down, used a torch tip cleaner to clean it and bam she idles so smooth.
Thank you for posting your final solution! Too many times folks come here asking for help with a problem but never come back to share their solution.
It certainly sounds like a blocked idle circuit on one side of the carburetor. I think you need to take it back apart and use some small diameter wire to trace the idle circuit along with a really good cleaning. Also, you shouldn't see any fuel in the carb throat at idle. You probably have the throttle plates far enough open to start pulling fuel from the main metering circuit. I have an Edelbrock carb that one day lost one side of the idle circuit. I pulled it apart and went through it and still had the problem. I was ready to pull it apart again when a buddy offered the Edelbrock carb off his hot rod. He put an off topic fuel system on it (FiTech).
Old shade tree fix /may' work.... With******* in park...fire the engine. Rev it up with one hand and clamp the other hand over the top of the carb. When it just about dies ....remove the hand and let it start to 'catch-up'.... then do the same thing again. Do that a 1/2 dozen times and see if that's the fix ! By pulling such a huge vacuum in the carb...most of the time any tiny chunks-o-crud will be*****ed through 6sally6
I have used the "engine trying to***** the bones out of your hand" method for 50 years, it has cleared the crud out many times, usually after an "expert" recommended a complete fuel system overhaul !
The theory is great, but the application leaves a bit to be desired The manufacturer placed a choke plate in the carburetor to allow choking the engine; use it! Backfires on a closed choke plate do not hurt so much as those on a hand! And yes, it DOES work! Jon
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