1988 Johnson Evinrude "CC" 9.9 thru 30 Service Manual, P/N 507660, Page 159Get this manual
Pyrometer Procedure 1Install correct test propeller and place engine in test tank ill
pTwist and remove remove spark plug leads before
changing propellers to avoid accidental starting of engine
2Start engine and run at 3000 RPM for at least five minutes
3 Reduce engine speed to 900 RPMAt 900 RPM digital pyrometer should indicate 1400 15 (60 rC) when held on the cylinder head If engine temperature is not within this range, troubleshoot cooling system to determine problem