Operating temperatures of 4 strokes - The Hull Truth

Bamaskeetshooter · 05-28-2009, 08:05 AM

Do 4 stroke outboards run hotter or colder than 2 strokes?

A1 Outboard · 05-29-2009, 06:36 AM

Oatboard motors all are limited to about 140 degrees of maximum temperature. 2 strokes and 4 strokes have different requirements. 2 strokes like to run warm at idle for better fuel atomization and a cleaner idle. Most 2 strokes bypass the thermostats at higher engine speeds to acheive more horsepower. 4 strokes need engine temperature for fuel atomization and to evaporate contaminates from the engine oil. Outboards cannot operate at temperatures as high as auto engines because of the corrosive effects of hot salt water.

marvin177 · 05-29-2009, 08:36 AM

According to my LMF 200 gauge my Suzuki 90 4 stroke runs at around 160 degrees.

A1 Outboard · 06-01-2009, 06:52 AM

Had some trouble finding spec. Manual shows thermostat opening at 122 degrees. The engine should run a little above opening temp. 160 seems a little warm, where does your gauge pickup engine temp?