Nanni Diesel running cold

[Mirage35]

And in answer to the original question, thermostat spec on our Nanni is 165. (N3.30, 29 hp on a 35 foot boat)

[Vila]

I just talked to Brook from Kraft Power in New Jersey at the boat show">Annapolis Boat show a week ago and he told me they have a complete inventory of Nanni parts. There phone number is 860-876-6102

[FPNC]

Your overpowered and not loading the engine. Which has a cooling capacity to turn a prop over 18" in diameter and push a 28,000 lb vessel at hull speed in tropical waters.

The standard Kubota engine of that type has a thermostat that starts to open at about 160° F and is fully open at about 180° F.

There have been Kubota thermostats available that open at higher temperatures. I am not sure if there is still one available for your particular engine.