MG Car Repair: Wonky power, gasket leaks, light flickers

Question
I have a '72 MGB with a new Weber 32/36 carb. It has a "flat" spot at around 2000-2500 rpm & sometimes "sneezes". I don't know if it's relevant, but the idle also comes and goes...it'll be fine and then "hiccup"....I noticed as well that the red ignition light flickers until I turn on an accessory..headlights or heater fan for eg. Any ideas? Thanks in advance.

Answer
Hi Ted,
The ignition light has nothing to do with ignition, it is a charge light so you should put a volt meter across the battery for that. Engine off read battery voltage then start the engine and set the idle at a fast idle and read voltage. It should read 13.8v to 14.5v, then let it idle and read voltage, it should be above the first "engine off" voltage. If not check belt tension and do voltage drop tests on + and - cables.

As far as unstable idle you should warm the engine up and remove the air filter and slowly cup your hand over the intake and slowly restrict the air until you choke it down. At no time should it smooth out or speed up. If it does, you have  a vacuum leak. Check for gasket leaks or vacuum hose leaks.

The "Sneeze" can be either a lean jet used or an engine problem. Do a compression test. (Throttle wide open and at least 4 or 5 revolutions on each cylinder) (should read 125 PSI to 180 PSI with little difference between cylinders)

Let me know,
Howard