MG Car Repair: 1973 mg midget, fuel pressure gauge, bright sun light


Question
QUESTION: I installed a weber carb. on my 1973 mg midget. It starts up and runs fine but
when I take  my foot off the accelerator the car stalls. please help.


ANSWER: Hi David,
Weber carburetors have a throttle stop screw to set idle speed and they have idle mixture adjustment screws too. You should purchase a Haynes manual on Weber Carburetors if you intend to keep it on your car. The manual covers adjustments on Webers.

Howard

---------- FOLLOW-UP ----------

QUESTION: i will buy the manual. now it wont start. flooded?


Answer
Hi David,
Most mechanics will tell you that the easiest car in the world to fix is one that won't start. A standard procedure MUST be followed and nothing skipped.

First is a compression test (throttle open) (compression gauges are not expensive)
If the compression test is ok and only if it is ok you can proceed to the next test. (compression test 125 to 165 PSI on all cylinders with little difference between cylinders)

Set the ignition timing to specs. Remove all the plugs and attach the plug wires to each plug and lay the plugs on a metal part of the engine and spin the starter and watch each plug fire. Spark should be thick and blue in color (not in bright sun light)

Only now can you look at fuel. First put a fuel pressure gauge on the fuel line that goes to the carburetor. Turn on the ignition (not start) and you should hear the pump running for a moment and it will slow or stop running and the pressure will read from 1.5 to 3 PSI (not higher)

With everything put back together and the air filter off have someone try to start the engine while you spray a little "Starting Fluid" into the carburetor. If the engine starts up and only runs for a second or two or as long as you keep spraying then you have a carburetor problem and need your Weber manual to go through it.

Don't skip anything and don't change the order. With this sequence of tests you can NOT fail to find the problem.

Howard