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MG Midget and Sprite Technical - Starter Solenoid

Quick question before I go out and buy a replacement solenoid for my 72 midget.

I've attempted to get my midget started after a 5 year lay-up. Car was turning over and sparking - then while poking about I managed to short out the solenoid. Now when I try to start it the solenoid doesn't click.

I can't find any fuses blown so I I'm assuming I've knackered the solenoid. Should there be a fuse in the cuircuit or is it a case of replacing the solenoid?

Thanks

Bob
Rob Storer

There is no fuse in the starter circuit.

Check that you are getting 12v on the white/red wire at the solenoid while cranking. If not, investigate why.

If you do have 12v while cranking, you need to check that the solenoid is earthing properly.
Dave O'Neill 2

Hard to see how a short would bother the solenoid much. Shorting the permanent live from the battery momentarily would make pretty fireworks but shouldn't be a problem otherwise. Shorting the permanent live to the primary live should just make it crank the engine. If you had the permanent live shorted to earth longer than momentarily I guess that might cook it though, and it wouldn't do your battery any favours either.

Dave is on the right track I think. Check you have power where it's supposed to be first, at the terminal where the battery cable goes. Then check continuity/resistance across the coil. Finally disconnect the thick wire going to the starter and see if you get 12v on primary live as Dave described; if so check for 12v at the big terminal that the starter cable came from when the primary is energised (eg: by turning the key).

Lastly make sure the solenoid to body earth connection is sound. It's not unusual for paint/corrosion/general crud to get in the way of solenoid earth.
Greybeard

Thanks to both of you for your reply. It's a couple of months ago I tried to start it so can't remember exactly what i shorted - I just know that since then the solenoid doesn't click and therefore the engine won't crank.

Thats a good check list there - so will take a a look over the Christmas break and hopefully get it sorted. New Year resolution will be to get it back on the road!

Thanks again and have a Merry Christmas

Rob Storer

Okay good luck Bob.
If you can't find a fault with the solenoid see if you can momentarily short between the terminal with the big cable from the battery and the terminal with the white/red wire (which comes from the key switch). A short end of fence wire usually does the trick but be cautious as it could get pretty hot. If that makes the solenoid see sense and crank the engine it would imply that the key switch and/or the white/red wire are at fault.
If the switch is u/s I wouldn't even bother replacing it personally. When the one in my campervan quit I bought a 10A momentary push-button for not very much and wired that in instead. I like that because you get the chance to hide your engine start button somewhere devious!

Happy Christmas to you as well.
Greybeard

Bob,
if after trying the suggestions for the starter solenoid you still have doubt about it then for the sake of £9 I'd replace it (with a good reliable new one, beware as lots of new made parts are crap) because at this stage, or any stage, you really don't want starting problems otherwise you can't get on to sorting other issues further on.

Mini Spares claim to have "Best quality available" STARTER SOLENOID WITH 3 TERMINALS (13H5952) -
http://www.minispares.com/product/Classic/13H5952.aspx

As with all electrics on the car you want all wires, earths and connections from the battery onwards to be clean, secure and protected and the battery to be good quality, in good condition and always well charged. A good battery in good condition and state of charge, with all connections in good condition, means you have more power to fault-find on electrical items and the running of the engine – a drained battery can hinder or stop the fault-finding process.

Good luck.
Nigel Atkins

I've known the situation where the battery terminal will pass low current but on heavy demand contact fails. Make sure the clamps are tight and clean too.
Graeme Williams

Quick note to finish this thread:

Replaced the solenoid and the engine now turns over fine. First time in 30 plus years of midget ownership that I've had one fail.

Thanks to all of you for your help

Bob
Rob Storer

This thread was discussed between 22/12/2018 and 13/01/2019

MG Midget and Sprite Technical index

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