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MG Midget and Sprite Technical - starter motor toast?

Hi,
I fitted a new battery to my IOW frog on monday and it started up just fine. Wanted to go for a drive today, turned the key, fuel pump operated as normal and solenoid gave 1 click but starter motor did not turn-no sound also.
Checked battery voltage (12.9v) and with ignition on measured 12v going into the solenoid. Also turned the pinion on the starter motor with a spanner and appeared free. Shorted across the 2 terminals on the solenoid, nice bang and sparks and starter motor turned but engine did not catch. Forgot to pull choke lever out so applied choke and shorted across solenoid terminals again. This time, absolutely nothing. Have i toasted the starter motor? Or am I missing something else? I fitted a new solenoid and repeated the procedure; again 1 click from the solenoid but nothing at the starter motor. I've checked and cleaned the leads from battery to earth, battery to solenoid and solenoid to starter motor.
I'm figuring the fault is downstream of the solenoid?
Any help gratefully received.
Andrew
aj robinson

How's your engine earth strap?

Also, you need a good connection between the starter and the engine.
Dave O'Neill2

and check the solenoid is earthed well underneath to the body

and the earth strap/lead from engine to body is a good, firm, clean connection at both ends
Nigel Atkins

ETA: sorry I somehow missed Dave had already put about the engine earth strap - just means you'll have to check it twice now ;)
Nigel Atkins

Hi,

my frog is fibreglass bodied and I have never been able to find an earth from the engine to the body, which makes sense really. It seems that the engine is earthed somewhere else but there are quite a few earth wires in the engine bay!
I will check the earthing of the solenoid as this seems a likely candidate and also the connection between the starter and the engine.
Many thanks,
Andrew
aj robinson

engine to chassis then, there will be a lot of earths as normally some items earth through the metal body, like the lights, etc.
Nigel Atkins

Unlikely to be the solenoid earth if it doesn't work when you short across the terminals.

If you don't have a hefty earth lead from the engine to chassis, or battery ground terminal, your starter may have been grounding through the choke cable!
Dave O'Neill2

Hi Andrew,
You have changed the battery. Are the battery connectors fitted tightly with a good connection? That would be the first thing I would check.
Next, the engine earth (bypass this with a jump lead from the engine to the battery earth terminal) and then the connections from battery to solenoid and then solenoid to starter.
You could bypass the solenoid and all wiring by connecting the battery direct to the starter with a big cable (jump lead) but be careful not to short it on anything.

Dave
Dave Brown

>>Unlikely to be the solenoid earth if it doesn't work when you short across the terminals<<
true but it did work first time and I think it's a good idea to cover associated areas even if not directly part of the solution, if you cover the whole system you're not just resolving the primary fault and getting the car started you're getting the car started well by covering more than just the primary fault
Nigel Atkins

Because it worked great with the new battry before and now does not and you replaced the selinoid with a new one, the only thing left is the starter

Id pull it out, give it a good cleaning, DO NOT LUBE it in any way, take it to auto zone type of parts store and have them check it... its almost.always free to test and install it dry...no lubes

I had a (flat spot on the windings) on the starter on my newist truck 3 years ago...it took a.while to figure out...because it wasnt very often that the starter hit the magic spot that made it a dead stick.

Prop

Prop and the Blackhole Midget

Thanks for the comments so far.
Battery connections checked and as I said, started first time when I tried it 3 days ago just after fitting the new battery.
The electrics on my car do not earth through the chassis; all the earth wires are led to a central point in the engine bay. From here, 3 large earth wires (not sure why a single larger wire isn't used) are attached to the engine block at the alternator bracket. The negative battery post is connected with a large wire to one of the gearbox bell-housing bolts. Although the car is fibreglass, I have never had any problems with the electrical components working and I had an auto electrician check everything 2 years ago.
Now today i ran a jumper from the solenoid to earth, and the starter motor briefly operated normally. However, when i repeated the operation, just a click from the solenoid. I'm starting to think Prop may be right, its the starter motor. Or something else intermittent?
I'll try connecting the starter motor direct to the battery tomorrow and report back. I'll also check continuity in cables from solenoid to starter motor and maybe battery to solenoid and battery to earth.
Regards,

Andrew
aj robinson

interesting on the way the earthing is done

it might sound daft Andrew but do check the electrolyte level in all the cells of you new battery and have look at the condition of the plates, also (again) check the new battery has good charge

too long to go into now but a mate of mine recently had a problem with a brand new battery and as in almost all the cases of battery faults it wasn't the battery at fault, so double check battery and main connections and earths
Nigel Atkins

Ok, removed starter motor today (complete pain), bench tested and it was dead. Luckily I had a replacement on the shelf, but have discovered the bolt holes are a smaller distance apart!!! By quite a way. I'm just wondering if it's from a mini or earlier A series (mine is a 1275 from 1967)
So I'm going to see if I can swap the plates with the boltholes around. I think the bendix is held in place with a circlip but has anyone else done this?
Regards,

Andrew
aj robinson

Also just realised the old starter has 9 teeth and the new one has 10. Does that make a difference?
Regards,

Andrew
aj robinson

Andrew,
have a look in the Archives here for both answers I know the 9/10 teeth came up recently but I can't risk my memory for a correct answer
Nigel Atkins

You need a bendix spring compressor to swap the bits over...or you could watch a video of John Twist using two pairs of mole-grips to compress the spring and nearly having a nasty accident!
Dave O'Neill2

Theres enough slop in the gears so a 9/10 are interchangeable

Do not oil or lube the starter...install it dry

Prop
Prop and the Blackhole Midget

"""you could watch a video of John Twist using two pairs of mole-grips to compress the spring and nearly having a nasty accident!"""

Flying Spring to eyeball, left pocket ???

Haha

Prop
Prop and the Blackhole Midget

This thread was discussed between 12/03/2014 and 14/03/2014

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