Drive belt is slack. Remove the blade and impellor (fan) look at the underside and you can see the blade pulley and towards the front you should see the motor drive pulley. The motor is mounted to the motor plate by four screws in slotted holes. Loosen the four screws and gently lever the motor towards the front of the mower- this will put added tension on the belt. Keep the tension whilst you quickly re-tighten the four motor screws. Replace the impellor and blade and test. If it is still running a slow speed then it is going to be a motor bearing starting to seize.
pleasant, September 2008
