well what you need to do is change the oil if you have done that then take the head off the motor clean the piston and the valves and the head if tha does not work take the motor off the mower and take the bottom of the motor of and pure kerocine in to the block and slush iy around then pour it out then put the motor back together and put it back on to the mower and try it agian.
tim, October 2008
