Raw Water Cooling

After the cooling failure on Memorial Day I’ve been messing with the system.  Simpler-is-better so I decided to leave the engine plumbed for raw water cooling.  That’s what it was designed for to begin with (Yanmar 3GM) and the fresh water system that was added by some previous owner was a hack-job at best.

I installed a SpeedSeal on the pump that is now the raw water pump and have ordered a Globe impeller.  I built in a flushing connection just after the raw water strainer that sends garden-hose water to the engine and back-flushes the strainer.  I can also close the intake seacock and the raw water pump will pull MarSolve into the engine through this connection.  I also installed a colder (125 degree) thermostat.

I built a similar connection into my old powerboat.  The engine itself was fresh water cooled but I used the connection to flush the saltwater side of the heat exchanger and the exhaust manifolds.  The manifolds and heat exchanger were both 19 years old when I sold the boat but they looked like new.

There is less stuff in the engine compartment.  There is also less stuff in the starboard cockpit locker.  The old fresh water cooling components were a bit corroded from many years of use without flushing.  It is nice to have that stuff gone.