Carb help on stock 2bbl.

[Blue71]

I am running a rebuilt (rebuilt six mos. ago) stock Motorcraft 2bbl carb on a '77. This unit was run on my '74 for a year and did fine. I took it off for a month and now put it on my '77. It just wont accelerate smooth when you snap the throttle fast. It bogs for a tiny second. If you ease into it, it accelerates smooth and fine all the way up to high RPM's. While accelerating hard while driving...it bucks once and kinda falls on its face for a split second, then accelerates fine. I have tried adjusting the two mixture screws under the front of the carb to about every setting possible,even the same settings as on my '76. I actually put the '76 carb on the '77 for kicks, and it ran crisp and clean, so I know its the carb. I just put on a new accelerator pump and it doesn't change. Help.

Thanks,

Blue71

 

[CDHUNTER]

Your looking in the right place with the pump shot. Chech to make sure both nozzles have a good squirt when you blip the throttle by looking down it and working the lever without it running. If you get two good streams you may have to adjust squirter size.

 

[mitzel]

The screws at the base of the carb affect idle only, I wouldn't mess with
them for this issue.

With the engine off and looking down the carb throat blip the throttle
and ensure you see a shot/misting of gas from the accelerator pump
discharge nozzles. That should tell you the accelerator pump is working.

The accelerator pump actuating rod has something like four holes it can
be inserted into on the throttle linkage end and I think two holes on the
accelerator pump lever. I'd start with all the adjustments set exactly the
same as on your other carb. Then you can tinker from there if it needs
more adjustment. I think if you go to holes higher up on the throttle
linkage it's a longer throw so that probably slightly increases the squirt.
The adjustments on the accelerator pump lever I think maybe affect the
rate/duration of the squirt. I haven't really played with those, always
have just set to stock adjustment.

Anyways that's what I think might be a useful start on diagnosing your
issue. good luck! danny