The engine heats up to max when you turn it off, so will present the greatest resistance to turning. The pistons will expand as the heat sinks into the block and head, not unlike the early stages of seizure through overheating. So this will find any weak spot in the system. I had major trouble with my Gilbern on hot starts.It often took 15 minutes before it would restart, and that turned out to be a weak starter. But the most baffling non-start I ever had was the battery positive terminal, on a rear mounted battery, which had a hairline crack. This only became obvious when I'd spent a fortune changing things, and as I fitted a new battery it fell apart in my hand. Fixed for £3.00, having spent a fortune first.
