The Kubota Tractor Corporation manufactures engines for lawn mowers and other equipment. It’s possible that after using your mower under extreme conditions, your Kubota engine will overheat. But if the engine seems to overheat prematurely, one of the cooling functions may be compromised. Consider these possible culprits before taking your Kubota mower in for service.
Kubota engines use motor oil to act as a lubricant between the moving engine parts, such as the pistons. Motor oil also transfers heat away from the pistons and the combustion chamber. If your Kubota mower has no oil, engine parts can seize up and melt onto each other from excessive heat. Always check oil levels before operating your Kubota mower. Inspect for any leaks around the drain and fill ports as well.
Oil also acts as a cleaner for your Kubota engine. As the parts are lubricated, oil carries away any debris introduced into the engine. Petroleum-based oil also has natural contaminants that can’t be removed from refining. As time goes on, motor oil burns up and leaves behind these contaminants. If it isn’t changed regularly, the oil loses its heat-transfer properties because it’s so full of contaminants. Be sure to change your oil according to what the user's manual recommends, which is typically after every 50 hours of engine operation.
Larger Kubota engines like the ones found on lawn tractors have breather systems that also help cool the engine. A breather tube runs through the engine and sends hot air to an exhaust system while simultaneously returning oil to the crankcase. The breather tube can be compromised if the breather reed does not open to allow the air out or if the air filter gets clogged. A crack in the breather tube may also leak air prematurely, preventing the force needed to push compressed gases through the exhaust.
Kubota diesel engines, which are used on their tractors, have a radiator-based cooling system. Ram air enters the engine through a grill. The radiator cycles cooling fluid around the diesel engine to transfer heat away from the moving parts. If the grille is clogged with grass or other debris, it restricts the cooling system. This also happens if the grille’s fins are bent out of shape, which prevents the air from being redirected properly. Also check the foam liner that acts as a shroud for the engine by keeping the cool air in.