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Carter bb-1 idle circuit??


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Hi all,


Having a hell of a time trying to get this carter BB1 (re-built) to work on the idle circuit.


It will only idle above 800rpm on the power circuit.

Adjusting the idle mixture screw has no affect at all, regardless if its screwed in all the way in or out.

As soon as I screw turn the idle screw out to lower idle level under 800 it will cut out.

Adjusting the power screw does alter the rpm from 800 to +1000rpm.

Will not start unless I push on the throttle pedal.


The ignition side of the engine (1928 Chrysler 62 - 180ci L6) is fine - it idles (at 500rpm) and runs fine with the Stromberg L1 carbie.


I have pulled apart the bb1 many times now looking for any issues on the idle circuit but cannot see anything obviously wrong.

I cannot see any blockages, the main jet that feeds both power and idle circuits has a ball in  it that moves freely.

I have the idle mixture screw 1 full turn out.


Can anyone throw ideals my way to sort this out. I am going bald....:(

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IMG_9202.jpgThanks Bob for the diagram, yours is a whole of lot better than the one that was supplied with the kit.


When I said 'main jet' in my first post I was actually referring to the 'Pump Valve assy'. the kit indicates that this supplies both. the idle and power circuits.

When you say 'idle jet' do you mean the 'idle orifice tube'? Is this meant to have a small hole in the bottom of it?


Edited by maok
Added pic (see edit history)
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Thanks for all the info. The diagrams and pictures. Im running a BB-1 that came off a running, 30 Chrysler, CJ-6,  that was being rodded.

I've been debating on weather to send the carburetor to be rebuilt professionally or do it myself.

You can't beat a man at his own trade.


Bill H

Edited by Bill Harmatuk (see edit history)
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