yanmar not cranking?

will it crank by hand socket on the crank shaft pully main bolt mabey a 20-25 mm take the rocker cover off if ur competent in using the spanners and taking ur time now to tear the gasket and try turning the engine over by hand and watch the valves for sticking. check oil for creamy deposits as will indercate heavy contamination from moister ever from short running of the engine or water in oil from broken seals. or head gasket gone... the fuel stop may be stuck closed to ? ..... turn engine clockwise :)

dave
June 2009