engine is ch20 s spec i think 64757 and is ohv its sounds like your starter motor solenoid / starter motor clutch assy is playing up , or solenoid is stuck
is the noise a grating kind of noise , could be pinion / ring gear -possibly s/m is loose or something jammed in there
is the noise a grating kind of noise , could be pinion / ring gear -possibly s/m is loose or something jammed in there