1999 EE Johnson Outboards 25, 35 3-Cylinder Service Manual, Page 124Get this manual
Retaining Ring Pliers
Thermomelt Stik Procedure
&Twist and remove spark plug leads before changing propellers to avoid accidental starting of engine1Install correct test propeller and place engine in test tank2Start engine and run at 3000 RPM for at least five minutes[] 3Reduce engine speed and run engine at 900 RPM for five minutesMark the cylinder head with 1250 (52 C) and 1630 (73 C) Thermomelt Stik
4At 900 RPM, the 1250 (52 C) mark should be 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 over cooling If the 1630 (73 C) mark becomes liquid and glossy, troubleshoot the cooling system for causes of overheating[] 5When the engine speed is increased to 5000 RPM, the 1630 (73 C) mark should remain dull and chalky If the mark becomes liquid and glossy, troubleshoot the cooling system for causes of overheatingo