Freshwater Engine Flush

As warm-water sailors, we do not winterize our boat. However, we do store it out of the water for hurricane season, and as part of our decommissioning procedure we run the engine on the hard to pass fresh water through the raw-water circuit and flush out salt and guard against corrosion. I also run the engine prior to launching to avoid any nasty surprises.

The trick to running an engine with the boat out of the water is figuring out a way to feed it cooling water. Over the decades I’ve done this many ways. The fitting illustrated here is by far the easiest and most foolproof method I’ve come up with. It works best with a basket strainer that has a removable lid and is located higher than the raw-water pump.

You’ll need the following components: a garden-hose end fitting with a shut-off valve, a molded U-shaped automobile engine hose, a hose barb and a single hose clamp. Once assembled, connect the fitting to a garden hose, hang it over the lip of the open strainer and open the valve enough to fill the strainer canister to overflowing. Start your engine and adjust the valve to keep a trickle of water overflowing the top of the canister. This assures an uninterrupted flow to the engine’s raw-water pump. Your automatic bilge pump will deal with the overflow.

You’ll need to increase the flow rate as the engine’s throttle is advanced, and someone should monitor the flow while the engine is running to make sure the canister is full.

Photos by Don Casey