18-0296 – OIL SEAL – Mercury Marine / Yamaha

The 18-0296 oil seal is a direct replacement oil shaft seal used on many Mercury Marine, Mariner, and Yamaha outboard engines. It prevents water and contaminants from entering the lower unit or gearcase while keeping lubrication where it belongs at the propeller shaft or drive interface. This seal meets most OEM dimensions with a 23 mm inner diameter and appropriate width to fit rotating assemblies.

Proper sealing on an outboard is critical because water and dirt can damage bearings and gears if they leak past worn seals. The 18-0296 oil seal fits into a housing bore and compresses around the shaft. It stops oil from leaking out along the shaft and blocks water from traveling in. This helps ensure smooth rotation and long-lasting support for internal driveshaft components.

If an oil seal leaks, you may notice lower unit oil loss or gearcase fluid mixing with water. This often leads to noisy operation, rough shifting, or early bearing wear. Replacing worn seals with the correct 18-0296 oil seal restores proper fluid retention and protects the drivetrain. Many listings note that this seal also replaces OEM numbers such as Mercury 26-83406M, 26-82233M, and Yamaha 93101-22067-00 in lower unit or prop shaft applications.

Shop at Arizona Outboard Dismantlers to keep your outboard running strong and ready for the water.