MG Car Repair: MG midget 1500, bright sun light, dual carriageway

Question
Hi there, I was wondering if you could help me out. I bought a Midget that had been sitting around for 4 years. It ran fine for a while, long journeys weren't a problem. After a while it started to fail to start in the cold. Started with a warm engine fine. Choke works fine. Got used to push starting it when I needed it (not often). Then the other day on a dual carriageway, it misfired (which its never done) and lost power half a mile later. AA dropped it off at the nearest garage where they said it was the points. Changed those, still doesnt work, and they say they dont do anything else on older cars. I am only a rather amateur mechanic myself! Any ideas?

Thanks

Answer
Hi Peter,
Your symptoms do not indicate what is wrong so tests need to be run to find the problem. All piston engines only require three items to run, Compression, Fire and Fuel with conditions on each.

When a car was brought to me in the dealership with such a complaint I had a procedure that I had to follow to find the problem. Compression test first. Pull all the plugs and hold the throttle OPEN and run the test on all four cylinders. You should see 125 to 160 on all four with very little difference between cylinders. This must be correct or it is a waste of time going any further. (a compression gauge is not expensive if you don't have one)

Since you already have the plugs out, connect the plug wires to each plug and lay the plugs on a metal part of the engine and have someone spin the starter and watch the plug gaps. You should see sparks at each plug and they should be thick blue sparks. (not in bright sun light) If you don't have spark then the problem is in the ignition. (let me know and I will cover the tests on the ignition system)

If you do have spark proceed to the fuel test. This one is easy as you just need a spray can of starting fluid (available at any auto parts store) Have someone try to start the engine and you spray a little starting fluid into the intake (after you put the plugs back in). If it fires off but don't keep running unless you keep spraying fluid into the intake, then you have a fuel problem.

When you have it pinned down to which section it is in let me know and I will cover the tests for that area.
Howard