Before you go thru all the usual possible problems,check the throttle control rod(it connects to the rod that passes thru the engine) check for play ,up and down,and side to side.If there is play?,the rod is worn out.my engine runs strong,but there is no way to control the RPM's,I ordered this part before the 4th of july,and in October, my dealer gave up trying to get a reply from B&S.He told me they were going thru a management change.The cost of the part was less than $20.00. I may run this engine until it blows,and then find a kohler as a replacement.