MG Car Repair: 1979 mg midget 1500 throttle linkage, stromberg carbs, zenith stromberg

Question
Howard -

The diagram you sent was not helpful.  I have a Zenith-Stromberg 150 CD-4T carburetor.  It is shown on page 89 of the current Victoria British catalog.  My vehicle is a 1979 MG Midget 1500.  In looking at the serial number, it was one of the last 500 manufactured in late 1979.

Anyway, my original problem was a broken throttle return spring which is located on the throttle shaft.  I had to remove the carburetor to get at it.  Getting the throttle linkage assembled is a pain.  It consists of the throttle lever return spring, the throttle return lever, another smaller unlabeled spring connecting the throttle return lever and the fast idle lever,a brass washer between the throttle return lever and the fast idle lever which the smaller spring wraps around, and finally a washer and nut.  Getting all of these items assembled properly and a put on the throttle shaft in the confined space available is very large effort.  I was hoping for some diagram with instructions somewhere to show me exactly how to do that.  I am sure that the idle adjustment screws will not work properly until I have properly assembled all the throttle linkage parts.

There are no such instructions or diagrams in the microfiche of the workshop manual I purchased from Heritage Motor Centre.  Nor is the Haynes MG Midget manual helpful
Any ideas?

I may not have the throttle lever in the correct position.  That could account for excessive air.  I will have to take the carburetor off again and check that when I am able to figure out how to properly assemble the throttle linkage.

Could it be a problem with the air regulator or the deceleration bypass valve?

Please let me know what you think.

Jeff


Answer
OK Jeff I see your problem now and I have some 150 Stromberg carbs and a small Brit car library so I will do some digging and see what I can come up with but it may take me a day or so. If I have one of your type carbs I will take the appropriate parts apart and lay them out and take a photo of them for you.

Almost all of the decell valves that I have seen in the last few years have the diaphragm hardened so that it can no longer open. On a few the small spring inside no longer could assure a closed valve so when the diaphragm was not readily available I just ran the adjusting screw so as to keep the valve closed all the time.

The idle air regulator can be removed and examined for a gasket leak so that can be easily eliminated as a cause.

I'll get back to you on what I find for the linkage assembly.
Howard