Urgent Diesel Engine Question

[Dockhead]

Great feedback. Thanks everyone.

So I guess the most likely culprits are:

1. Exhaust elbow
2. Thermostat
3. Impeller or slipping belt.

I'll work through those and see what happens.

Concerning driving the boat beyond hull speed -- maybe, at max throttle. But the engine won't develop more than its rated maximum power anyway, and the cooling system should be able to handle that. Right?

Anyway, the overheating starts far earlier than approaching hull speed.

[Rex Delay]

Don't forget to check that intake hose. I always like to start with the simple cheap stuff and work up to the more expensive/complicated fix.