Stromberg cd150 question

[George_H]

I bought a 79 midget for my wife this fall and I'm starting my winter projects on it. The carb is running very rich so I pulled it and started pulling it apart for cleaning and rebuilding. When I pulled the "air piston" I noticed that there is about 3mm play side to side with the piston all the way down. I have had a few Triumphs (now and in the past) With the larger 175 carbs, but this is the first 150 carb I have worked on. I don't remember that much play in the others. Is this much play normal or should I start looking for a carb, and dump this one before I go any farther down the line with this one? Thanks, George

 

[bthompson]

From what I remember from mine, it was a little loose in the bore, but not nearly to that extent. Since the vacuum is held with a rubber diaphragm instead of the piston itself, the tolerances don't need to be nearly as close as SU pistons are. I'd be more concerned if that side-to-side play was causing the needle to rub in the jet. '79s have spring-loaded needles, right? Could be that the jet has run oval with time...that'd cause the rich running too.

From my experience, you're gonna have a devil of a time getting that Stromberg to not run terribly rich. Several here have substituted an SU from an MGB (HIF6, I think) that mates to the stock 1500 intake manifold with very little trouble. The Weber DGV kits are a good swap, too.