For our engine replacement, the Beta 25 uses larger raw water hoses. I decided to replace the entire raw water system. I upgraded the thru-hull to a 1″ fitting, and added a water flow alarm switch into the intake side of the raw water pump. I also rerouted the new 1″ hoses between the heat exchanger and the exhaust injection nipple to shorten their run and to get the anti-siphon closer to the boat’s center line.
I added a 2×2 to the back of the bulkhead to mount the anti-siphon. It also made a good place to attach the PSS vent to make sure it was also always above the water line. I stained and varnished it to help it blend in. It is not perfect, but good enough for the aft cabin.
Water flow alarm switch
Cooling hose routing
Anti-siphon mounting
Update:
The water flow alarm switch was not sized correctly for this engine. Even the smallest one still required more flow than the Beta 25 produced at idle, so it would alarm whenever the engine was below about 1500 RPMs, even though there was normal water flow. It also added strain on the fitting to the sea strainer, so I decided to remove it.
