Heat Exchanger Installation Info

Two days ago I replaced the heat exchanger, hoses, gaskets in raw water strainer, impellers in both pumps, all belts and the engine over temp alarm switch. I learned from Grant that raw water cooled engine alarms are set lower than fresh water cooled engines. The replacement temp switch is for a fresh water cooled with a 65 C trigger point. Raw water engines use 60 C. I had to borrow some sockets to change the sender so a new 1/2 drive & socket set was added to the boat tool locker. Here is the P/N of the new over temp sensor:

Below is a hookup diagram/parts list for the coolant hoses.

I was appalled to see that the impeller on the freshwater pump lost one of its vanes after only 2 years of service. It was a Yanmar part too...

Today I installed two stainless hose clamps around the lower body of the heat exchanger to prevent cracking of the mounting lugs. The heat exchanger came without the clamps unfortunately this time. The old unit had the clamps from the factory 18 years ago.

The raw water pump would not pull seawater through initially until the strainer was primed with water. In past work on the cooling system I don't recall having this issue.