Jimmyk;
Two symptoms here: First the possibility of a rich condition as evidence by the spark plugs, second the whistling somewhere in the carburetor throat. I would investigate the choke system first.
To conduct the proposed test the entire air filter/silencer will need to be removed.
With the engine fully warm and running try rotating the choke plate in the direction of ‘choking’ the engine. Easy does it, just a little bit of force against the bimetal with your finger . . . not enough to alter the mixture. After that try pushing the choke plate to the full open the position . . . hard against the stop. Did the whistle sound change during this test? If it did then let’s start looking at the choke adjustment, especially if the noise stops when the choke is full open. It other words, if the whistling stops when you push the choke full open I’ll go out on a limb and say the choke is not adjusted correctly. Later we might want to investigate the choke vacuum piston condition, but that’s a subject for another day.
I’ll be first to admit my experience with your Stromberg carburetor is extremely limited, but some of the design concepts appear to be the same as the later Carter designs. If the choke vacuum piston detail is an area of similarity, I believe once the choke plate achieves the full open position the air flow in that system is blocked by the motion of the piston, therefore the air flow in the choke system should be zero, or near zero with the plate full open. The Stromberg Manual available on this site (see StrombergManual.pdf (packardinfo.com) does not specifically state the cut-off function, but the artwork on page 2 (page 15 of the PDF) suggests air flow cut-off is likely with the choke full open. The integrity of the choke vacuum passage ‘Welch Plug’ should also be inspected. If in doubt a bit of paint along the outer diameter of the plug should seal it well enough for you to determine if that’s an area that will need attention. In the same vacuum passage there appears to be a lead plug, again a bit of paint will seal that area for enough time to conduct the test. The choke circuit might whistle during warm-up but somewhat silent after that. The above testing is only trying to determine if whistling airflow is associated with the position of the choke plate and therefore the piston position. The Welch plug and lead plug if leaking will whistle independent of the choke plate position.
dp
Edit: I can't seem to get the links to work correctly when using Word as a means to compose the message. Perhaps someone with more savvy will help.
https://packardinfo.com/xoops/html/downloads/StrombergManual.pdf It works OK when I paste directly into the posting, but not when using Word.
This Post was from: https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=256928