1993 Johnson Evinrude "ET" 90 degrees CV Service Manual, P/N 508285, Page 124Get 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 temperatureWhen the surface exceeds the Stik's rated temperature, the mark will appear liquid and glossyTo achieve accurate and 'consistent readings, engine temperature must be gauged at the top of cylinder head To troubleshoot and isolate cooling system problem properly, be sure to test both cylinder heads
r::=J For the following engine operating temperatures and RPM
figures to be correct, the inlet water temperature must be 700 100 (21 30 C)Pyrometer Procedure 1Install correct test propeller and place engine in test tank