1997 Johnson Evinrude "EU" 90 thru 115 90 CV Service Manual, P/N 507267, Page 128Get this manual
Thermomelt Stik Procedure 1Install correct test propeller and place engine in test tank
To avoid accidental starting of engine while servicing, twist and remove all spark plug leads
2Start engine and run at 3000 RPM for at least five minutes
3Reduce engine speed and run engine at 900 RPM for five minutesMark both cylinder heads with 1250 (52 Cl and 1630 (730 C) Thermomelt Stik
4At 900 RPM, the 1250 (52 C) marks should remain liquid and glossyThe 1630 (73 C) marks should remain dull and chalky