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carbs one more time [at least]

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69tr

Jedi Trainee
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I have determined that the carbs that I bought were from a '72. The tag # is 3777 L/R. I have them cleaned, rebuilt and installed on on the car. The car started fine and seems to run ok. It is still running lean. I lifted the pistons on each carb just a little and the rpm's dropped and the car stalled. I turned the mixture adjustment to the stops both ways and it did not make any difference. Do you think that lowering the floats a little would help? Is there any adjustment on jet height?

Thanks again, Pete
 
69tr said:
I turned the mixture adjustment to the stops both ways
Click to expand...
Normally I'd say that indicates some other problem, like a vacuum leak (have you tried plugging the line to the brake booster?).

Check out Nelson's articles on the Buckeye site for a method of temporarily moving the mixture adjustment richer. IMO that is a lot safer than trying to reposition the jets.
 
A lot of times the needle carrier come off the threads of the needle adjuster screw and no matter which way you turn the adjuster, the needle won't move.
There are less than 3 threads so you don't have all that much to play with.
The needle won't fall out of the air valve, though. There's a screw in the air valve that keeps the needle in place, while still allowing a bit of verticle movement.
 
BTW, adjusting the mixture by lifting the piston is somewhat of an art.. Lift as close to 1/8 inch as you can. Practice, be consistant, find a screwdriver blade that has that dimension on the blade or shaft is a help. Anyway you do it, make your determinatin on the immediate response of the engine. A couple of seconds holding the air valve up while you try to decide, and the engine will probably want to die anyway, unless it's really rich.
For a starting point. I'd turn the adj. screw fully CW then CCW 1 1/2 turns.
Oh yeah, after a few minutes of just sitting there idling, the carbs will probably load up. The Manuals warn about this, too: so just rev up and hold it high for 10-15 seconds, clearing them out and resume.
 
Float levels that are too low will cause a perpetually lesn condition no matter what you adjust.
Having said that, I would heed the advice above and check for vacuum leaks and that the needles are attached to the carrier before messing with the float height.
 
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