Powertech Generator/Kubota overheating

[GregOConnor]

It may work to add a screen to the inlet side of the fan cage. maybe a filter is too much as it would probably be ok to let dust just blow past the radiator. The design issue is that the collection point for sucked up debris is the flat horizontal radiator face. once the fan is turned off ,there is no gravity acting to pull the surface clean like it does with a upright car radiator. A screen to the inlet side of the cage fan would stand vertical and debris would drop once the fan stops sucking air in that side. if you only let dust in to the fan cage or particles as small as the radiator fins can pass, you can then just wash out the radiator with a hose. the screen would need to be removable to flush wash the radiator fins.
While in that radiator compartment I removed my AT relay and replaced it with a 80 amp breaker marine switch. the A.T. relay stays hot and sucks up major amps (phantom draw). there are a couple of other electrical items close to the frame of the bay door that I also replaced and updated with marine grade relay/switches. I had a electrical ground short in that area when vibration caused the frame of the bay door to contact a 100 amp lug. (the stray voltage also forced a fault light on the allison display but no code when I hit freeway bumps for months)
The debris you cleaned out was most likely the cause of lugging of the old motor because the motors effort was hitting a solid wall and could not push the air it collected. the opposite of plugging up a vacuum hose. But it doesn't hurt to replace a 20 year old vital component. damaged motor was a result not a cause.