Mercury Mariner 8/9.9HP 4-Stroke Factory Service Manual, Page 7Get this manual
General Specifications Model 89.9
HORSEPOWER (KW) OUTBOARD WEIGHT FUEL Model 8.0 (BODENSEE) Model 9.9 (BODENSEE) Model 9.9 Manual Start Electric Start Recommended Gasoline Engine Oil Capacity F
+100 +80 +60
8.0 (6.0) 9.9 (7.4) 9.9 (7.4) 102 lbs(46.3kg) 107 lbs(48.5kg) Automotive Unleaded with minimum pump posted octane rating of 87 Either 1.0 quart (1.0 Liter) SAE 10W-30 viscosity oil is recommended for use in all temperaturesSAE 25W-40 viscosity oil may be used at temperatures above 40 (4C)Use Quicksilver 4-Cycle Marine Oil with the proper viscosity for the expected temperature in your area (see chart above)If not available, use premium quality cycle engine oil, certified to meet or exceed anyone or combination of the following American Petroleum Institute (API) Service Classification SH, SG, SF, CF-4, CE, CD, CDII+38 +27 +16 +4 18