1997 Johnsoon Evinrude "EU" 50 thru 70 3-Cylinder Service Manual, P/N 507266, Page 143Get this manual
Thermomelt Stik Procedure 1Install correct test propeller and place engine in test tank&
Twist and remove the spark plug leads before changing propellers to avoid accidental starting of engine
2Start engine and run at 3000 RPM for at least five minutes3Reduce engine speed and run engine at 900 RPM for five minutesMark the cylinder head with 1250 (52 C) and 1630 (730 C) Thermomelt Stik
4At 900 RPM, the 1250 (52 C) mark should remain liquid and glossyThe 1630 (73 C) mark should remain dull and chalky If the 1250 (52 C) mark does not remain liquid and glossy, troubleshoot the cooling system for causes of overcooling If the 1630 (730 C) mark becomes liquid and glossy, troubleshoot the cooling system for causes of overheating