18. Operating temperature

Like all internal combustion engines, the Atomic 4 would like to run around 180 degrees. However, the designers were concerned about salt precipitating out of sea water at temperatures much above 150 degrees, so they installed a thermostat rated at 140 degrees, which in most areas will maintain an operating temperature between 150 and 160 degrees (depending on outside water temperature).

Several years ago, Westerbeke came out with a 180 degree thermostat for people operating in fresh water areas or for engines with fresh water cooling systems installed, particularly in cooler climates (like the Great Lakes, Lake Champlain, etc.). In our experience, the 180 degree thermostats create a few problems in warmer waters where just a small amount of fluctuation in operating conditions can cause temperatures to overshoot into the 200 degree range. Effects of running in the cool range (95 to 100 degrees) include increased carbon buildup on valves and rings. Eventually, both the valves and rings can stick, and compression will suffer. Of the two effects of running too cool, sticky rings are the more difficult to cure. - Updated: November 4, 2003