1990 Johnson Evinrude "ES" 60 thru 70 Service Manual, P/N 507873, Page 132Get this manual
Pyrometer Procedure
1Install correct test propeller and place engine in test tank
Twist and remove spark plug leads before changing propellers to avoid accidental starting of engine
2Start engine and run at 3000 RPM for at least five minutesr:;] 3Reduce engine speed to 900 RPMAt 900 RPM, digital 15 (60 C) when held on the cylinder head
L!J pyrometer should indicate 140
If engine temperature is not within this range, troubleshoot cooling system to determine problem