Adjusting carb for major altitude change

[PH Nelson]

I am moving from 5200' altitude to 150'. What change do I need to make in the carb settings on my B-4-B?

[greg g]

Probably none.  You might need to reset idle speed as it may increase due to slightly different air fuel ratio.

[kencombs]

If, and it is a big if, it is properly and precisely jetted for your current altitude it will be lean at the new location.  Maybe someone who has the proper factory manual can tell us what jetting was used for delivery to say Denver vs LA.  I think I've seen that somewhere but don't remember where.  It is probably not correctly jetted for your altitude unless shipped to some place like Denver when new.

 

 

You could  have a local shop with proper fuel/air ratio instrumentation check it out.

 

Or, if you're into such things, install your own instrument using a wideband O2 sensor and associated gauge.

 

 

In either case adjust jet sizes if needed.  I'd bet only the idle speed and mixture will really need adjustment.

 

[Plymouthy Adams]

the factory manual has the stock jet size listed and the traditional -1 size lean jet for the higher altitudes.  First you have to establish if your car was adjusted at the mixture for this area or actually changed to the smaller jet...time to dig in and get to the truth...

[Fernando Mendes]

WWII GMC CCKW 1944 recommend that in HIGH ALTITUDES use short stroke of accelerator pump(Zenith carburetor).In Carter B&B has a similar procedure to put to short stroke.