Cooling System

The engine has a two-circuit cooling system, with a fresh water system circulating through the engine block, exhaust manifold, and expansion tank, and a sea water system. The sea water enters the boat through a sea cock and a sea water strainer on the starboard side of the engine, running through the priming pump (at the starboard foremost corner of the engine) and the engine oil cooler (on top of the transmission) to the tubular heat exchanger (starboard side of the engine block). The strainer has a transparent lid, fastened with a wing nut, which can be removed for cleaning.

(Always close the sea cock first.)

In the heat exchanger, the sea water cools the fresh water. From the heat exchanger, the sea water runs through the transmission oil cooler (on top of the transmission) and a “swan neck” (with anti-siphoning vent above water line) to the exhaust manifold outlet, where it is mixed with exhaust gas and expelled through the exhaust pipe.

The exhaust hose is made of reinforced rubber, and the muffler of stainless steel. The thru-hull fitting of the exhaust pipe has no shut-off valve.

Winterizing Sea Water System

When the boat has been hauled, fill the sea water system with one or two bucketfuls of a fifty-fifty fresh water/anti-freeze mixture by undoing the entry hose at the strainer, dipping the hose in the barrel, and letting the engine run until the exhaust gas starts containing anti-freeze mixture, which will show by the color.

Should you want to empty the sea water system, drain by undoing the drain plug under the muffler and undoing the entry hose from the strainer. Also, drain oil coolers from their respective drain plugs.