Sierra 10W30 4-Stroke Conventional Marine Oil

Conventional 10W30 formulated for four stroke outboards and sterndrives rather than cars. The difference that matters on the water is corrosion protection: a marine engine sits for weeks with condensation in the crankcase, and an automotive oil is not built for that duty cycle.

• 10W30 conventional four stroke marine engine oil
• Meets or exceeds API SJ, CF-2 and CH-4, and is NMMA FC-W certified
• Formulated for Mercury, Yamaha, Johnson-Evinrude, Suzuki and Honda four strokes
• Corrosion protection, anti-wear additives and sludge control
• Quart and gallon, with case quantities available

Change it at the interval in your engine manual and do it at the end of the season, not the start. Leaving used oil in a crankcase all winter is how bearings get etched.