1993 Johnson Evinrude "ET" 40 thru 55 Service Manual, P/N 508283, Page 149Get this manual
Engine Temperature Check The Markal Thermomelt Stik is heat-sensitive marker that melts on contact with surface of specific temperatureOne source for Thermomelt Stiks is Stevens Instrument Company
rv At least twoaccurately determineorthedigital pyrometer should Thermomelt Stiks be used to engine's operating temperaturesThe Thermomelt Stik mark will appear dull and chalky when the surface marked is below the Stik's rated temperature When the surface exceeds the Stik's rated temperature, the mark will appear liquid and glossy
rt To achieve accurate and consistent readings, engine temperature must be gauged at the top of cylinder head700 For the following engine operating temperatures and RPM figures to be correct, the inlet water temperature must be 100 (21 30 C)
Pyrometer Procedure
i lers; twist and remove all spark plug leads