Perkins 4.108 Cooling Question?

[Dougal]

Our 4108 is raw water cooled, and it seems there's always something more important to suck money away than converting to indirect.
Is it possible to make this old lump (the motor not me) run a little hotter? It never even makes it to 55 or 60 degrees!
Could it even be as simple as finding a different thermostat?

 

[sneil]

Any hotter and the below will happen.

Salt water tends to build up a corrosive scale when the engine operates above 60°centigrade. In the raw water system this scale is building up inside the engine's water jacket and ports. When the scaling builds to the point that water flow is restricted the engine starts to overheat. At this point you are probably looking at replacing the engine.

 

[No Regrets]

One of the reasons non-performance boats are set to run cool (Often by drilling a hole in the Thermostat) is to stop the Hot-Cold-hot-Cold cycles which eventually damage the engine.

This works well on Rivers with locks, where you will be turning the engine off every hour. The engine runs at a more even temperature and it doesn't appear to affect the running at all!