slow cranking when hot

[RalphG]

If timing is advanced too much it will try to "kick back" the piston before it hits top dead centre. Making the starter hesitate every compression stroke. Also I remember six volt tractor starters that were fine cold but barely able to crank the engine when hot. We changed the starter and it made a huge difference. Some problem with the fields? Been too many years to recall but I know the changing the starter cured the hot start tractor problem.
And I don't recall seeing a starter brace to the pan rail on any of my flatheads. All crank over pretty good hot or cold.
And I don't see how the condensor can have any effect at all on cranking speed of the starter.