Oil Pump Gearbox Lube Kit | 3/8-Inch Metal Swivel | Outboard Boat Motor

This hand oil pump screws onto standard quart bottles to fill outboard gearcases cleanly. Pumping from the bottom drain hole pushes air out through the top vent, preventing air pockets. The marine lower unit gear lube pump includes a threaded 3/8-inch metal swivel ring for leak-free fluid transfer. Features and Benefits - Threaded 3/8-inch metal swivel adapter - Fits standard gearcase drain ports without leaking fluid during fills - Fits 32-ounce gear lube bottles - Screws right onto standard quart containers so you avoid messy pouring - Long flexible discharge tubing - Reaches tight drain plugs under the anti-cavitation plate easily - Positive displacement hand pump mechanism - Moves thick marine gear oil smoothly even in cold shop conditions Applications - Lower unit gear lube servicing on Mercury, Yamaha, and other major outboard engines - Seasonal fluid changes on sterndrive and inboard gearcases using quart gear lube bottles - Winterizing marine lower units before cold-weather outdoor storage What It Is This product is a manual hand oil pump designed for marine gearbox servicing. It features a 3/8-inch (9.5 mm) metal swivel fitting that connects directly to the lower unit fill port. Operating entirely by hand without external power, it delivers gear lubricant from the container into the outboard boat motor casing. The rigid metal fitting provides a secure connection to stop leaks during filling, helping you direct heavy marine oil upward into the gear housing until the correct level is reached. Key Uses & Applications This kit is built specifically for lower unit oil changes on outboard boat motors. Routine maintenance tasks include: - Pumping gear lube into outboard lower units via the 3/8-inch drain hole - Topping up marine gearboxes cleanly without spills or air bubbles - Transferring heavy lubricants where gravity feeding is impractical For general workshop fluid transfers, tradespeople often keep siphon pumps nearby. When learning how to use a siphon pump or how to use siphon pump setups for light fluids, place the source container higher than the destination, establish flow using the hand primer, and let gravity pull the liquid through. How to Choose Select your fluid transfer gear based on liquid viscosity and the machinery being serviced. For outboard gearboxes, check that the threaded drain plug matches this 3/8-inch (9.5 mm) metal swivel fitting. Standard marine gear lubricants are thick and require direct mechanical pumping from below, rather than siphon action. If you are dealing with thin fuel rather than heavy gearbox oil, standard category siphon pumps are the right alternative. Anyone asking how to siphon gas with a hand pump needs a fuel-rated kit, chemical-resistant tubing, and a clear path from a raised container, avoiding mechanical gear lube pumps entirely.