Benedix sticks in flywheel, tried 3 starters, crankcase not overfull. Also has new battery and checks 12.47 amps, cleaned all cable terminals. However, if charger is put on battery all seems to work OK.

Hi,
I gather you mean the gear though you have omitted an engine make. Does it have a working spring-loaded mechanism to make it drop away from the flyheel?
Peace,
Clakre