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MG Midget and Sprite Technical - Starter Motor Kicking Out

Hello.

I am trying to diagnose a problem that a friend of mine is having with his 1971 midget.
When he attempts to start it using the ignition switch the starter turns the engine over briefly, it disengages, stops turning, makes a humming sound for a second or two and then nothing.
The odd thing is that his car has a remote solenoid on it that has a push button that allows one to turn the engine over by pushing it. With the ignition switch off he can push the button and the starter turns the engine over effortlessly. If he puts the ignition switch to the on position and then pushes the solenoid button it reverts to the failure mode as described above.
To me it looks as if a voltage drain is being created when the ignition switch is on. Does anyone have any idea of what the usual suspect is for this type of drain or how to figure out where it is? He has been going through connections and cleaning them up. Could there be another cause?
A few other things.
In the not too distant past he was able to start the car, although he says that starting has always been sluggish... kind of hit and miss.
It is not the battery. He has tried starting while boosting from another car and no improvement.
He has installed a new ignition switch and no improvement.
He has tried a second starter and no improvement.
Thank for your help. This is a real mystery. Tim
Tim Mayor

Has he checked the ignition timing?

If it's too far advanced, it may be stopping the engine, instead of starting it.

Try setting static timing to 10º BTDC and see if it improves.
Dave O'Neill 2

Not to solve this problem but generally especially for startling have good clean, secure and protected earths, engine earth particularly for starting.
Nigel Atkins

Ground cable between the chassis & the engine / starter? Bad internal electrical connection in the remote solenoid?
Stan Kowznofski

like Dave O. my immediate thought is ignition timing too far advanced....
David Smith

Thinking about that other discussion about ballasted ignition systems; when did they introduce ballasted circuits in the USA cars? Or has it been modified?

Maybe the main coil feed is missing or faulty and the coil is only getting the feed whilst the starter is in circuit?
GuyW

Tim,

The starter is supposed to disengage when the engine spins faster than the starter. It is likely that, in your case, the engine is firing enough to kick out the starter, but not enough for the engine to continue running.

That is why people are suggesting you check things in the ignition system. You might also check to see if the mechanical advance of the distributor has frozen in place.

I think your theory that a high draw when the key is turned on is unlikely to be the cause of the problem.

Charley
C R Huff

http://youtu.be/PQ9mvwY71lo

Hi again. Thanks to everyone for their responses! I believe Charley is correct. I am working remotely from my friend and have been going by his descriptions. I now have a video, linked above that shows it trying to start. It seems to be firing. He was going to static time but found seeing the timing marks extremely difficult as they are on the bottom of the engine (why would they have put them there?)so he just loosened the distributor was going to turn it slightly and try starting the car. For some reason he could not turn it clockwise. When he turned it counter clockwise and tried to start it just kept on cranking over. That tells me it was not firing anymore. He marked the original distributor location and can return it to where it was.
So I guess the question now is why won't it keep running? Carburetor issues? He has recently been cleaning and fiddling with the carbs. Thanks again. Tim
Tim Mayor

At the risk of teaching you to suck eggs, when did it last run properly? If recently, then whatever has been fiddled with is probably the problem.

If not recently or many things have been fiddled with then start from scratch and check everything as per the manual.

You might get lucky and jump straight to the right thing, but with an engine in an unknown state going through it systematically can be faster and less frustrating.

--- list ---

Set tappet clearances, remove plugs and do compression/leakdown test, run through ignition (points gap OK/timing set*/leads in correct 1342 order/plugs cleaned and gapped or renewed), with plugs out and resting on the head crank over and test for even strong sparks**, then carbs (float bowls full, piston movement free, choke movement free, butterflies synchronised, jets centered, jet height correct), fill with fresh fuel and it will start and run.

*If the timing marks are inconvenient, locate TDC for #1 while you have the rocker cover off and plugs out and paint on some better ones.

**if no sparks here, suspect distributor cap, capacitor, coil or low voltage wiring.



AdrianR

Wow, I thought putting my usual (as below) but that's a lot more comprehensive. I agree if so much has been done it's been forgotten/mixed up then start back checking the basics.

And it often pays to check again what you're already checked and rechecked.

Set up tappets, CB points, plugs, timing and mixture in that order, if you have to adjust any item in that chain then you’ll also need to check, and adjust if required, all the items that follow it in the chain.
Nigel Atkins

After careful re-reading of the first post I think it must be an ignition timing issue.
Based on the information that the solenoid works fine and spins the engine UNLESS the ignition is switched on.

Or did I miss something. Again.
Greybeard

It's pretty much what I had to do to mine to get it running again after a long lay up. It did fire up initially, but then ran very roughly and going through the list I found a few things weren't right, e.g. corroded exhaust value, sticking choke and worn points.

Yes, could be just timing but Tim says "starting has always been sluggish... kind of hit and miss." so I'd still give it all the once over.
AdrianR

Hello Folks.

A big thank you goes out to everyone as my friend, thanks to you pointing him in the right direction, has been able to get his Midget started! It was the distributor! Really badly worn bushings??
I've posted a short video of it to YouTube here http://youtu.be/bCbIgulXUtY and a video of the startup http://youtu.be/96ANTz2tvlE .
The distributor that was in it was from a Land Rover I believe. I've attached a picture. Luckily many years ago he salvaged everything he could from a 1968 Midget that had been sitting in a field and was going to a junkyard. He put that distributor in along with new points, cap and condenser and it fired right up. I'll post a picture of the Distributor from the 1968 in the next post.
Thanks again everyone. You've been very helpful.



Tim Mayor

The distributor he installed from the 1968 Midget


Tim Mayor

Ah, now I see the problem. The dizzy cap is missing.

LOL - just teasing! Good work Tim.
Greybeard

Tim,
well done to your mate.

Hopefully this is the end of it but just a few words of caution and advice just in case. It might not be the case for the new parts your mate has bought but new modern made parts can be poor quality so make your friend aware of this just in case of sudden or intermittent running problems.

The points will need checking after a few good journeys to make sure the gap is the same and of course checking and servicing the dissy at the service intervals.

Bit of a downer I know but best to be forewarned in case more problems crop up.

If that rotor arm is modern made and has a rivet be aware of the following (red isn't just about the colour) -
http://www.distributordoctor.com/rotor_arms.html
Nigel Atkins

This thread was discussed between 30/06/2018 and 08/07/2018

MG Midget and Sprite Technical index

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