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Q & A: Tune-Up

Hi John,

I'm restoring a 74 MGBGT(Rick Brown's daily driver) and a 80 MGB in which I'm at the tune-up stage. The ignition system is all in good working order. New plugs, wires, cap, rotor, coil. Valves adjusted. Carb dismantled, cleaned(pretty sooty), new parts too. {diaphram, gaskets, vacum line, Manual choke(water choke removed), gulp & check valves, air pump,air filter, intake-exhaust manifold(planed, new gasket, no leaks), egr valve sealed ,fuel pump & filter etc. It appears a "relativley" small fire melted the throttle cable and did some paint damage to the underside of the hood(no other visable signs of fire).
So.. It starts fine, idles fine(850rpm), accelerates fine, shuts off fine at idle, But, doesn't return to idle. It doesn't appear to be a mechanical problem(every thing moves smoothly). With the air cleaner off you can push the piston down and the idle returns to 850. Maybe a vacum on top of the piston holding it up and not dissapating? Oh, I tried 30 wt. in the damper-No idle return, replaced it with Moss Z-S carb dashpot oil (thinner) and still No idle return. I ordered a new spring for the overrun valve in the throttle disc. Do you think thats it? It looked OK but who knows? We're out of ideas.... I would greatly appreciate your advise. This is my first encounter working on Stromberg Carbs so I'm learning as I go. But a friend is helping me out with this. Thanks for your time and if you need more information Brian

PS How do you check-top off the shocks? level on ground? jacked up evenly? Squeeze it into the top nut till it runs out? Steering boots and rear end...90wt....Hypoid or non-hypoid?

Brian!

I'll put my money on the spring loaded valve -- the overrun valve -- on the throttle disc. Remove the carb and solder this shut. Also note that the car will NOT run properly with the air cleaner off.


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