Hi
In the hot weather my Ruby will sometimes not want to restart. The engine seems to have poor compression as there is very little resistance when tuned over on the handle, but it always starts well from cold and runs fine. I know the timing is right - I can feel a slight kick back on the handle when turned over slowly with the ignition switched on. So I have always thought the hot starting problem is due to vapour lock as a result of the more volatile modern fuel - though I do use the premium BP petrol. As it only happens in the warmest weather, I have done nothing more about it other than contemplate fitting a four blade fan.
Regards
Colin

Location: North Cheshire