<VV> I'm thinking maybe the starter motor...

[FrankDuVal]

Hugo:"But why - and indeed how - would a winding 'fail' when hot?"

Response: It is not a winding, but the bushings that change dimension 
when hot. They wore while cold, now the worn bushing is changing shape 
due to heat, and capturing the armature shaft at a different place than 
when new. Replace the bushings. And the brushes while you are in there.

Now, it could be a bad connection that increases resistance with heat 
also....  aka Chuck's solenoid contacts idea, but any connection in the 
starter might be the culprit. Heating of the connection should be 
obvious when it is taken apart.

Frank DuVal


On 8/6/2020 10:11 AM, Hugo Miller via VirtualVairs wrote:
> I would vote for the latter. If it's a mechanical fault, there is no 
> reason why it should only happen when hot - especially as the starter 
> has more work to do when cold. I've experienced it on a number of 
> vehicles - the most embarrasing being a 10 litre diesel in a 
> double-deck bus. You would swear the battery was flat - but leave it 
> to cool down & it will spin over as good as new.
> But why - and indeed how - would a winding 'fail' when hot?
>
> On 2020-08-06 15:00, Jim Becker via VirtualVairs wrote:
>> I'm pretty sure it is the coriolis effect because they didn't put a
>> left hand spiral on the Bendix.
>>
>> Seriously, when you take the starter apart, the reason us usually
>> obvious. The armature has been dragging on the pole shoes.  New
>> bushings will usually fix it.  If this isn't it, the problem could be
>> a winding that fails when it is hot.
>>
>> Jim Becker
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