You could take the starter motor off and pull it appart and give it a good clean, you might be surprised how dirty they can get ,I have had that exact problem quite a few times on different ride-ons and all the starter motor needed was a good clean and while your at it give the solenoid a good clean and make sure all your connections are clean both on the solenoid and starter. Sometimes it has just been dirty connection or the connection vibrates loose,Cheers.
Last edited by roebuck; 01/01/14 10:55 PM.