HELP: HOW DO I ADJUST, FINE TUNE MY HOLLEY5210-C?

[ski.dive]

I just purchased my 1977 vega from out west & the carb is set for [high elevation]
I live at 'sea level' in Florida, the carb is missing and running rough, NEED TO ADJUST IT TO SEA LEVEL
****Again, if anyone has 'simple instructions' [WHICH SCREWS TO TURN] on how to adjust the holley 2 barrel carb. on a 1977 vega, I would appreciate it.

`THANKS FOR ANY HELP

[cosvega76]

If your carb is truly calibrated for high altitudes, it's going to take more than a simple adjustment to correct it. It will also need jetting changes and maybe other carb circuit changes, as well. It may be easier to just swap the carb for a "sea level" version.

What problems are you experiencing?

Chuck

[cjbiagi]

The only "simple" adjustments you can do is with the idle mixture screws. Those are adjusted by either connecting a vacuum gauge to a full time manifold port and adjusting them for the highest vacuum reading or you can also use a tachometer and adjust for the highest rpm. When you are done then readjust your idle speed. As Chuck mentioned, it really depends upon what mods were done to the carb as far as jet changes. If that was done then you need to get it back to a stock baseline with the proper stock jets ( I have no idea what size those are) and go from there. It may be something else though, have you checked timing or done anything else?

[monza355]

Clyde,
if you adjust using the vacuum guage, does reducing the idle speed interfere with the vacuum reading or once you have the highest vacuum reading it will remain there even with adjusting the idle? I am about to get a new carb for my 355 and will have to do the same thing to get it right. Thanks.

[monza355]

Anyone?

[cjbiagi]

If you are doing it with a vacuum gauge don't worry about the effect it has on the idle. Just adjust for the highest vacuum and once you have achieved that adjust the idle speed where it needs to be. If you want after you have reached this point you can go the extra step of fine tuning the adjustment with the vacuum gauge again but it's probably not going to change much. Just realize that adjusting the idle mixture screws will change the idle speed so you will have to readjust it when you are done.

[monza355]

Excellent. Thank you very much Clyde. I think I can get this done now.