Problem My friend has a Kawasaki FH500v motor on a older great dane mower. This spring it had a issue where the cooling fins were very clogged and the motor went into thermal runaway and got very hot and would not run right after that. After reading some posts on this site we found that the plastic parts in governor might have been damaged. Upon cracking open the case it was found that this was the problem, as the plastic and ball bearings were not as they should be, in fact the plastic parts were just black clumps in the bottom of the pan and the bearings were also in the bottom of the pan. Repair Replaced the plastic retainer and the 6 bearings that make up the governor, also replaced all gaskets pertained to the repair, all intake gaskets, all throttle linkage and springs and one head that had a bad oil seal and it now runs ok but.. New Problem Upon starting the mower runs great but the governor will not go back to idle after the throttle is raised. The governor has been adjusted to spec (counter clockwise throttle and governor) and every other way just to try it. The governor arm does not seem to fall back down as it should, if you manually push it down it will idle down and stay that way until it is raised again but it will not do so by itself. We have opened up the motor again to check that the governor is installed correctly and everything is free and installed as to spec. The only thing that was not changed was the governor shaft seal, it weeps a very little but according to some posts we have read here replacing it might not change they minor problem. Any help or suggestion would be helpful. Thanks in advance.