Small Engines (Lawn Mowers, etc.): poulan riding mower, hp sounds, combustion chamber

Question
my husband replaced starter and battery. because it would not start it tries to turn over but it wont completely turn over. is there any way it could be the clutch not kicking all the way in. it is a poulan pro riding mower 18.5 hp

Answer
Sounds to me to be in the compression release system. As the piston moves up and down among the combustion chamber, it gains great pressure within the cylinder. The compression release relieves that pressure so the starter can turn the engine over during starting, then kicks out when started. You will more than likely have to bring it to your local repair shop. To correct it means removing the engine from the mower frame, and splitting the engine in half to find the component thats hanging up...........Tom