1992 Johnson Evinrude "EN" 40 thru 55 Service Manual, P/N 508143, Page 148Get this manual
Markal Thermomelt Stik Procedure
i lers; twist and remove all spark plug leads
'" Avoid accidental starting of engine while changing propel-
1Install correct test propeller and place engine in test tank2Start engine and run it at 3000 RPM for at least minutes141 3Reduce engine speed and run it at 900 RPM for minutesMark the cylinder head with 1250 (52 C) and 1630 (73 C) Thermomelt Stik4At 900 RPM, the 1250 (52 C) mark should appear liquid and glossyThe 1630 (73 C) mark should remain dull and chalky If the 1250 (52 C) mark does not appear liquid and glossy, troubleshoot the cooling system for causes of overcooling If the 1630 (73 C) mark becomes liquid and glossy, troubleshoot the cooling system for causes of overheating5When engine speed is increased to 5000 RPM, both marks should appear dull and chalky If either mark appears liquid and glossy, troubleshoot the cooling system for causes of overheating&