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MG Midget and Sprite Technical - Midget won't start

Hi again

I have a rather annoying issue on that the car will now not start.

In the past it did start flawlessly, however on the last attempt the engine did start but it was diffcult to get it to do so, it did start in the end but ran roughly and it did not appear to be running on all 4 cylinders, over the next 30 - 60 seconds it slowly died and came to a complete stop and refused to restart.

I have changed the battery to a brand new one and the engine turns over a lot better but it still doesnt start, it catches as if it is going to fire up but then turns over again.

Could the timing be causing this issue?

I'm starting to wonder if I am meant to own a mg!

Any thoughts as usual gratefully received.

R Williams

fairly likely to be burnt out or closed up points?
David Smith

Rylan. Fuel, spark, and compression are needed if the car is to start and run. Check for spark by pulling the coil lead from the distributor cap and having someone turn the engine over as you hold it near the block using a pair of pliers with an insulated handle. If you get a good, strong spark (should jump a half inch to the block), insert a number two phillips screwdriver into one of the spark plug terminals (after you reattach the coil lead to the distributor cap) and check for spark again. If you do not have spark, you have an ignition system problem. If you do have spark, remove the air cleaners and put a little fuel into the intake manifold (hold up the SU pistons and squirt about a teaspoon of fuel into the intake through each carb. Then, see if it will start.

A compression check, throttle held fully open, is always in order and should be done at least annually.

Les Bengtson

Wilst you need to do some testing along the lines determined by Les I would have a quick gamble on that suggested by David.
The very first thing to check is the points, are they opening and causing a spark?
Robert (Bob) Midget Turbo

If you do the points don't forget to do the timing after because it will change. If you don't it may still be close enough for it to run but not perform very well.

Could also be on 3 cylinders because one of the HT leads is loose.
Greg H

You are indeed correct in your diagnosis that your midget hates you, the only possible solution to this is to send it to me forthwith, with no hesitation or delay so I can thrash it at the next couple of autotests that I have no car for!!!!

This is such a generous offer that you would be foolish to give up on :)

Alternatively, get a voltmeter and check that all the wires are working - slightly more boring than sparks!

Rylan, I'm guessing this is a 1500? The clue to this is "it catches as if its going to fire up". I'm also guessing it catches but when you release the key from the start to the run position, it stops? These are classic symptoms of a Ballast resistor failure.

A quick check is to run a new wire from a brown wire on the fuse box directly to the + terminal on the coil. if the car starts and runs the Ballast resistor (which is a special wire in the harness) is bust. ******* WARNING*********
do not leave the temporary wire in place for any extended running as it will burn out the coil.

Options are:-

1, replace the coil with a standard 12v non ballast and run a permanent wire to it from the ignition switch (or the fuse for the ignition fed items)
2, find out what the Ballast resistance should be and replace with one from a electronics supplier such a Maplin (you will need to work out the wattage of the resistor required or someone here might have that already)
3, replace the harness!

All the other checks mentioned by others are to be recommended as you progress the trouble shooting

Good Luck

M McAndrew

I check for carb or fuel supply faults by using EZ-Start, as the engine begins to faulter or refuses to start spray a little into the carb mouths, if this helps the situation then there is some evidence of a fueling issue.

But as points need servicing on a routine basis anyway I would fit a new set and check the gap, and the static timing. If you have a strobe then also the dynamic timing.

I would also follow advice on checking ballast resistors, and spark strength.

James Eastwood

Nobody has mentioned the condenser yet - so I will!!!! I think the advice given above is right. If a car runs OK and then suddenly starts misbehaving it is most likely something electrical (and less likely a failure in the fuel system although that is possible).
Chris H (1970 Midget 1275)

Do the basics first. Check the ignition for a spark. Then check for fuel at the carbs.
Once you have found which side it is then you can single out the fault.
I had a Triumph Stag which failed to run and found it was a crack in the rotor arm, so check everthing from the coil to the plugs.
the easy way is to remove a plug refit the lead and rest the plug on the engine block so it forms a circuit, get someone to turn the ignition key as though they are trying to start the engine, you should see a spark in the plug gap. Keep your hands or any part of you body well out of the way when doing this as the shock from a ht circuit is quite painfull, so i believe.
If there is a spark then turn to the fuel system. Check the pump is delivering fuel to the carbs, is there a blockage in the fuel tank ? Has the pump packed up ?
If there is fuel then it maybe fine tuning. Set the timing, etc
If the car was running well before this started and you have done nothing to the engine then it is probably just a simple component failure.
Hope this helps.
Good luck
S Langston

This thread was discussed between 12/04/2011 and 13/04/2011

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