Join Date: Nov 2010
Location: West Jefferson, Ohio
Sounds like the needle and seat is getting stuck open.
Mine used to give me a kinds of trouble (the carb in general). It was to the point I could pull it off the motor, take it apart, fix whatever was wrong, put it back together, bolt it back on, and then have it running again... all in about 15 minutes... even outside when snowing.
In short, it's a very simple carb that a teenager with little experience can master.
Also, I ended up having an accelerator pump bore that was warped, and there was now way to get rid of an off-idle stumble. I put on a Holley 4bbl and never looked back.
'69 Impala 4-door hardtop
'70 Impala Custom coupe