Hey guys here's the story. Was driving the mini yesterday and was smooth. After bout 20min drive stopped at set of lights waiting to turn, clutch in gear selected. All of a sudden the car stalled, completely died and wouldn't crank over again.

Towed it to cousins place check battery spark fuel all good but still wouldn't crank at all. Trailered it home today and this arvo went over it again, thought the clutch might have seized the crank?? So I took out starter motor put it in 4th gear then rocked the car and flywheel was spinning freely so bolted starter back on and it cranked and started 1st go!!

Anyone had the same problem or know exactly what happens?

Your started motor looks like it was stuck on the flywheel. If it happens again put it in gear and rock the car until it turns over a few times then try starting it

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1964 smooth roof panel van
1967 Mk 1 X-Police cooper s
1970 mini k
1975 leyland

Even tho the starter is brand new?

Ring gear on the flywheel is probably worn, from the starter pinion crashing into it in the same place.
Cure- remove flywheel, cut old ring gear off, heat shrink a new one on.
Or, fit a Holden Gemini starter. These are pre-engaged, mesh from the engine side, and don't chew the ring gear up. Also, will work with your existing ring gear.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

so its possible for a new starter to stick to the flywheel and cause it to stall while the cars idling? I thought once the car is started the starter "disengages" and return to normal position?

If your starter motor was stuck to the flywheel when driving for 20 minutes you would know about it unless you are actually deaf. Would not cause it to stall unless the starter seized up after 20 minutes of spinning lol.

Sounds like possibly an electrical issue, without more info i would suggest checking the earth connection at the battery and the motor. It may be ignition switch issue or who knows what.

Did you have any problems previously? You mention it's a new starter motor, what was the reason for replacement?

Yea there was no noise it was just idling and turned off. I changed the starter as the old 1 wasn't engaging just kept spinning

No, not when running. What happens is you somehow stall the car, then when you crank the starter, the pinion goes into the worn (maybe burred) flywheel teeth and jams. When you unbolt the starter or turn the end of its shaft, the pinion comes back out. Perhaps worse with a new starter because pinion teeth and bushes are not worn.

See my post above for remedies...!

If the ring gear teeth are just a bit burred you can use a file or die grinder to remove them, once the flywheel is off. But for a proper fix, see above.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yea the remedy I'm going with is to rebuild the whole motor. Just trying to figure out what exactly happened. The thing I thought was the problem was maybe while waiting at the lights with the clutch pressed in that somehow it seized the crank like maybe a worn thrust bearing or something and with the heat of driving. When it stalled and I tried to start it there was no noise at all from the starter trying to engage that's why at first we checked the battery

The solinode base plate is an earth. Make sure its clean and corrosion free. Including the mounting bolts. If the connection is poor in this area the starter circuit will not work.

Had a simular problem with my moke.
Any sign of a green tinge on any of the connections is a giveaway.

If you hear a `click' and the starter doesn't turn at all, it could be the starter solenoid is worn inside. The copper contacts arc and burn away, eventually no go. This can be intermittent, just before it fails completely.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Could be a coil lead not making a proper connection or something? Definitely sounds electrical

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1968 Mini-matic - 1340cc, 45 weber - 92hpatw, 14.5 @91mph, GrandmaSpec

Definitely not electrical. Everything had power even the starter. It sort of seized up wether it was crank flywheel or starter or something else. When I took starter out and rocked the car it started straight away. Just weird it did it with no noise or warning

They are symptoms of a damaged/worn ring gear.
As said needs a new one, but I'd fit a Gemini starter instead. Quieter, more reliable, and no jamming.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Kev what year Gemini and engine size is the starter from.