11 replies to this topic

[venkman]

Hello,

Tried to start mini after electrical issues. The starter spins but doesn't quite engage to spin the motor. The very first go turned engine a 1/5 of a tun if lucky, what I'd like to know is, the starter more than likely caput or can you take it apart to free up the small cog so it moves more freely. It will turn by hand but its quite stiff.
It's a 91 Cooper so pre engaged starter with piggy back solenoid

Thanks

[stuart bowes]

the starter is actually a fairly simple bit of kit to take apart. clean up and put back together

 

you want to make sure the brushes have nice clean sharp edges no burring, their springs are good and the little plastic pieces hold them in securely, the insides can be all cleaned out, give the whole thing a good blasting with electrical contact cleaner and an air line

 

clean up the solenoid, reassemble all of it, test again and chances are it''ll work again

 

if not it hasn't cost you anything but time and elbow grease to find out 

 

the cog is quite hard to turn by hand, that's totally normal, partly because you can only just get finger tips on it 

 

i did mine quite recently https://www.theminif...-998/?p=3771363

Edited by stuart bowes, 31 December 2024 - 08:22 PM.

[bpirie1000]

Centrifugal force throws the small cog onto fly wheel..

You should be able to turn the small starter cog by hand..

Some lubrication may be required..... remember your clutchnis in there.. not toooo much... just enough......

Can test the starter with jump leads and a battery make sure the solenoid throws the small cog round..

Plenty videos on YouTube..

Edited by bpirie1000, 31 December 2024 - 08:22 PM.

[stuart bowes]

it was my understanding that the solenoid is what moves the cog into position, not centrifugal force (or is it centripetal...)

 

the solenoid operates on a kind of see-saw which pushes it into place 

 

it's possible im getting confused with the 2 different types, the one I'm talking about is the one in my link previous post

[Lplus]

It's a pre engage starter guys....

 

If the starter isn't engaging with the ring gear properly then the solenoid idn't moving the starter cog far enough.  Maybe grot on the shaft? or maybe a faulty solenoid? 

[venkman]

Thanks everyone, I'll have an investigate in next couple of days and report back

[venkman]

the starter is actually a fairly simple bit of kit to take apart. clean up and put back together

you want to make sure the brushes have nice clean sharp edges no burring, their springs are good and the little plastic pieces hold them in securely, the insides can be all cleaned out, give the whole thing a good blasting with electrical contact cleaner and an air line

clean up the solenoid, reassemble all of it, test again and chances are it''ll work again

if not it hasn't cost you anything but time and elbow grease to find out


the cog is quite hard to turn by hand, that's totally normal, partly because you can only just get finger tips on it

i did mine quite recently https://www.theminif...-998/?p=3771363

That's the same, glad of pictures it's clearer for me to understand. Thhanks

Edited by venkman, 01 January 2025 - 07:26 PM.

[coopertaz]

is starter ok on jump lead test then check battery negative connection to boot floor and one to bulkhead in engine bay, corrosion or slackness here will seem like a flat bettery and could give symptoms you describe

[Midas Mk1]

is starter ok on jump lead test then check battery negative connection to boot floor and one to bulkhead in engine bay, corrosion or slackness here will seem like a flat bettery and could give symptoms you describe

This, spot on. Basic checks first for power at the starter and solenoid, ground etc, before any stripdown or removal. 

[venkman]

Well it's been stripped down all cleaned and back together........same problem as before but then after many more tries I now have nothing but a click. Power is coming to starter, earthcable at battery is definitely earthing.

I kinda on the idea a new starter is required ?????

Even when on bench I can't get it to spin out!!

Edited by venkman, 02 January 2025 - 07:55 PM.

[stuart bowes]

I would just double check your testing method, may well be right but just to be sure

Firstly use a known good source, I used jump leads onto my volvo with the engine running.

Ground lead onto body of starter where the bolts connect it to the clutch housing

+12 onto the terminal nearest the starter first of all, that should make the motor spin but no clicking, you're bypassing the solenoid

Then move the +12 onto the other main terminal further from the motor, nothing happens at first but you get a fat screwdriver and bridge to the secondary terminal on that side. That's when you get the click, the solenoid operates, the cog jumps outwards and spins

Fingers and loose clothing well clear of the cog of course

That should tell you which bit is failing

[68+86auto]

You need to measure the voltages when trying to crank. The quickest way is to put the meter between the starter battery terminal and the starter case. Check that the voltage stays above 9.6v when trying to crank. If that is ok, check that the wide spade terminal also gets above 9.6v when trying to crank.