Sierra Introduces a New Kit to Take the Mess Out of Changing Outboard Gear Oil

by David Proudfoot

Until now, checking, changing or topping up the gear oil level in the lower unit on your outboard or stern drive meant one thing – grabbing plenty of rags because this task was guaranteed to cause a bit of a mess. Those days are gone, thanks to Sierra’s new Lower Unit Fill/Drain Kit.

This ingenious kit features two fittings that permanently replace the upper vent plug and lower drain plug in your Mercury or Evinrude/Johnson outboard or stern drive lower unit. They are machined from marine-grade 304 stainless steel to stand up to the unforgiving effects of salt water and feature a ball check valve that prevents any outward flow of lubricant. The lower fitting contains a small magnet that attracts and holds metal particles suspended in the gear oil, and also comes with a debris cap for protection.

outboard oil kit

Service adapters are provided for each of the lower unit fittings. These adapters, also made of marine-grade 304 stainless steel, are threaded on one end and barbed on the other to accept a hose or tube. When screwed into the fittings the service adapters disengage the check valves, allowing fluid to flow in and out of the lower unit through the affixed hoses and into appropriate containers.

A stainless steel key-ring tool is included to make it easy to install the fittings, remove the debris cap and to depress the check valve of the lower drain plug. Depressing the check valve releases a few drops of lubricant for a quick, no-mess inspection.

The Sierra Lower Unit Fill/Drain Kit takes the mess out of changing the gear oil in an outboard or stern drive lower unit. In addition, it makes inspection easy which in turn encourages more frequent checks – and longer gear life.

For more information on the Sierra Lower Unit Fill/Drain Kit, or any of the hundreds of Sierra Engine and Drive Parts, please visit

Facebook Comments Box

You may also like

Leave a Comment

I accept the Privacy Policy

This site uses Akismet to reduce spam. Learn how your comment data is processed.