1999 "EE" Evinrude 5 thru 15 4-Stroke Service Manual, P/N 787022, Page 164Get this manual
15Inspect valve housing, spring, and valve for excess wear or damage16Remove oil pan and gasket from powerhead
17Remove two screws retaining thermostat coverCarefully, remove cover and large springDiscard gasket18Remove washer and diaphragm and cup assembly19Remove vernatherm, small spring, and housing