1995 Johnson/Evinrude Outboards 25, 35 3-Cylinder Service Manual, Page 125Get this manual
Engine Temperature Check The Markal Thermomelt Stik is heat-sensitive marker that melts on contact with surface of specific temperatureOne source of Thermomelt Stiks' is Stevens Instrument Company
OJ At least two Thermomelt Stiks or digital pyrometer should
be used to accurately determine the engine's operating temperaturesThe Thermomelt Stik mark will appear dull and chalky when the surface marked is below the Stik's rated temperatureWhen the surface exceeds the Stik's rated temperature, the mark will appear liquid and glossy
To achieve accurate and consistent readings, engine temperature must be gauged at the top of the thermostat pocket
I Note For the following engine operating temperatures and RPM figures to be correct, the inlet water temperature must be 70 10 (21 e)Pyrometer Procedure
Twist and remove spark plug leads before changing propellers to avoid accidental starting of engine1Install correct test propeller and place engine in test tank