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Zenith Stromberg basic adjustment


Freshman Member
Hi all! I'm new to these forums here. I was wondering how you basically set up the twin carbs if I don't currently have the carb. tools. I'm just trying to see how the car runs. I bought a rust free 76 TR7 Victory Edition that would run when starting fluid was put in but would soon die right after. I have done the following. Rebuilt carbs, cleaned the filter element in the fuel pump, replaced all vacuum lines and fittings, all new rubber fuel lines(at least in the engine bay), Rebuilt the air pump ( yes it is staying completely stock)new wires and plugs. I also have a fuel filter that I haven't fitted yet. I tore apart the alternator and cleaned the rectifier of rust and dirt with a wire brush and then coated everything with dielectric grease. I've cleaned all ground points and coated them with dielectric grease as well. I'm just trying to get everything like this done so when I start it for the first time I could decrease the possibilities of any problems. I'm going to take the engine out this winter so I can send the shell off to get the front strut tower replaced. /ubbthreads/images/graemlins/mad.gif(previous owner nailed a curb I believe, which popped the welds at the top of the tower away from the top of the fender rain channel. There is about an 1/8 inch gap between the panels at the top...) I do have a rust free front end coming in from Arizona to replace the damaged pieces. Then she gets stripped and painted the original color of Pimento red when she is done. Whew!!! Sorry if I rambled, there is just so much I have done and got to do. I'm still learning about these cars. Any insight is appreciated. Cheers! /ubbthreads/images/graemlins/cheers.gif


Luke Skywalker
I think you'll at least need a Stromberg Mixture tool. They're only a couple of bucks, and you can pick them up from Moss Motors, Victoria British or probably from someone on Ebay.

There are very few adjustments on Strombergs (or any constant depression-type carbs.) You'll want to slacken the linkage between the carbs and first you set the mixture with the mixture tool, which I think in the 175CDs actually moves the needle down and up against the jet. (In SUs, you move the jet up/down with the idle mixture setting.) You'll know if you have the right mixture two ways: you can manually raise the piston just a hair and the engine should momentarily rev just a tad, then fall off. Also your spark plugs will be clean -- no fuel or detonation.

Set both carb mixtures.

The other adjustment is idle speed, which is the screw that pushes against the throttle linkage. You'll either want to use an airflow meter, or just put your ear right up to the carb and listen for equal "whoosh" of air. You want them sucking the same amount of air. Then you can tighten the linkage between the carbs.

You'll also have the dreaded deceleration bypass valves -- which are the things on the right side of the carbs. If the car is slow to decelerate, one of the valves could be floating. To remedy this, you unhook and plug the vacuum advance from the carb then turn one adjustment screw all the way out, then turn the other in until the engine races to 2500RPMs, then back it off to normal idle. Then turn the other one in and out the same way.

This is just a primer, but not entirely detailed -- so it just gives an idea.

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