1990 Johnson Evinrude "ES" 60 thru 70 Service Manual, P/N 507873, Page 131Get this manual
Engine Temperature Check The Markal Thermomelt Stik is heat-sensitive marker that melts on contact with surface of specific temperature One source for Thermomelt Stiks is Stevens Instrument CompanyAt 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 glossyf21 To achieve accurate and consistent readings, engine temperamust be gauged at the top of cylinder head
INotel For the following
engine operating temperatures and RPM figures to be correct, the inlet water temperature must be 10 (21 C)
Thermomelt Stik Procedure
1Install correct test propeller and place engine in test tank
"'" Twist and remove spark plug leads before changing propellers to avoid accidental starting of engine