The ultra 300 does have cooling issues due to the shallow water jacket design on the cylinders. When running full throttle under heavy load or on hot days, the machine usually does not get adequate cooling. A sign of this is speed reduction when the engine gets very hot. The ultimate solution is upgrading to 310 cylinders and installing our 310 conversion kit here. Obviously, if you do not want to remove the engine or spend that kind of money, this is a great option. It will definitely help keep temperatures down and increase reliability. Will require drilling and tapping. Drill and tap included with kit. Removing the exhaust manifold is recommended to make this easier. You will need replacement exhaust gaskets.