Hitachi ex 120-3 keep running hot. Replaced new water pump, had Radiator rodded out. Put new gauge and new thermostat. Does anyone have any suggestions what I should try next. I have also put a new conversion kit on it. Thanks for any advice.
Once you have replaced the electronic regulator with a mechanical regulator, engine overload is very common. When the engine is overloaded, it will of course lead to overheating. To completely handle the problem of the machine overheating: 1/- Replace the original electronic regulator for the machine. 2/- Recalibrate the mechanical regulator for accuracy, this is difficult! Requires technicians to have a deep understanding of the machine.
I have the same machine and had the same problem. I chased it for a while with some of the same solutions you did then I cleaned the oil cooler, condenser and radiator. In my case there was so much build up of crap in the oil cooler and condenser that it wasn’t allowing the radiator to cool.
How is the foam around the radiator? It needs to be all there in good condition otherwise the air flows around, not through the radiator.