1998 Johnson Evinrude "EC" 9.9 thru 30 HP 2-Cylinder Outboards Service Manual, Page 137Get this manual
Thermomelt Stik Procedure 1Install correct test propeller and place engine in test tank
&To avoid accidental starting of engine while changing propellers, twist and remove all spark plug leads2Start engine and run at 3000 RPM for at least five minutes
3Reduce engine speed to 900 RPM and mark the cylinder head with 1250 (52 e) and 1630 (73 e) Thermomelt Stik
4At 900 RPM, the 1250 (52 e) mark should remain liquid and glossyThe 1630 (73 e) mark should remain dull and chalky If the 1250 (52 e) mark does not remain liquid and glossy, troubleshoot the cooling system for causes of overcooling If the 1630 (73 e) mark becomes liquid and glossy, troubleshoot the cooling system for causes of overheating
ill 5When the engine speed
is increased to 5000 RPM, the 163 (73 e) mark should remain dull and chalky If the mark becomes liquid and glossy, troubleshoot the cooling system for causes of overheating