Packard Forum Index » Pre-War (1899-1942)

Hi all,
The idle adjustment on my car seems to have increased for some reason and I'm not sure how to adjust it back to a slower amount of revs. The carburettor is a Stromberg duplex down-draft model, I don't know it's designation #. Can some one tell me the easiest way to adjust it please. I can only see three adjustment screws. one coming off the choke control and two screws off at the front of the carb.
Many thanks in advance
T

Hi Terry. Your carburetor is (or should be) a Stromberg EE-22 with the 1-3/16 venture size (std. Eight was 1-3/32). The two (brass) screws facing forward are the idle mixture screws. The idle speed adjusting screw is at the rear on the inside, next to the manifold, with a spring around it. The head faces upward. It's possible you may also have to lengthen or shorten the throttle link rod to the cowl (turnbuckle) if you can't get a proper adjustment.

If you want to adjust your idle mixture with a vacuum gauge, there is no provision for that on the intake manifold but over where the vacuum lines converge for the power brake selector and Bijur lubricator there is a removeable plug for that purpose.

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Cheers Dave,
Is there a procedure for the adjustment? Do I just back off the idle screw or must I fiddle about with the idle mixture screws? I don't want to upset anything that will affect the running of the car. As always your help is much appreciated.
Take care
T

The proper way would be first set the idle speed to something reasonable although there is no specification that I'm aware of. If you have a 6-volt 4-cylinder dwell/tach (because it's really two 4-cylinder ignition systems) try about 375 rpm; otherwise as low an idle speed as the engine is comfortable with and resists stalling - mine idles comfortably and reliably at 350 rpm. Then install your vacuum gauge where indicated in the prior post and adjust the idle mixture to the maximum vacuum without extending the mixture screws beyond that point, or do it by-ear if you don't use a vacuum gauge (which is recommended). Then go back and reset the idle speed. Then recheck the idle mixture on more time.

But really if you haven't done it, you should first check and adjust if necessary the ignition timing on both #1 and #6 cylinders to get the best optimization. If #1 is timed properly and #6 isn't (or the reverse) you'll have to synchronize the twin points, or do it by trial and error; adjustment is made via the set of points on the moveable plate for #6 after timing #1 in the conventional manner.

Good info Dave, I'll give it a shot after I come back off holiday.
T