Lower Unit Gear Oil Pump – Fits Mercury/Mariner, Johnson/Evinrude, Yamaha, Suzuki Outboards (Replaces Various OEM Adapters)

Product Details

This universal marine Lower Unit Gear Oil Pump is designed for easily filling or refilling gearcase oil in most major outboard and sterndrive lower units. It connects directly to standard 28mm quart gear lube bottles and includes multiple adapters to fit Mercury, Mariner, Johnson, Evinrude, Yamaha, Honda, Suzuki, and more.

It serves as a direct functional replacement for other aftermarket pumps, including the JLM MARINE, Slippery Pete, and LOZAGU models.

• Simple hand-operated pump delivers 10cc of fluid per stroke for controlled filling.
• Includes a flexible 19.5-inch hose for reaching fill ports in tight spaces.
• Comes with 3/8-16, 8mm, and 10mm metal adapters to service most marine engines.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For all Mercury, Mariner, Force, and MerCruiser models, use the included 3/8-16 steel swivel adapter.

For Johnson, Evinrude, and OMC models, use the included 3/8-16 steel swivel adapter.

For Yamaha, Honda, Suzuki, Nissan, and Tohatsu models, use either the 8mm or 10mm adapter fitting as required.

Technical Specs

Product Type

Lower Unit Gear Oil Pump

Installation

Hand-operated manual pump

Fuel Type

N/A - For gear oil only

Connection

28mm standard quart bottle threads

Housing Material

Plastic with metal adapters

Housing Color

Black/Clear

Dimensions

19.5 inch (495 mm) hose length; pump body approximately 6 inches (152 mm)

Weight

170 g (0.37 lb)

Fitting Type

Multiple adapters included

Thread Size

3/8-16 swivel, 8mm-1.25, 10mm-1.25 adapters

Working Pressure

Hand pump (8cc/10cc per stroke)

Other Technical Attributes

Features both long (6.125 inch/156 mm) and short (4.75 inch/121 mm) suction tubes for different bottle heights

What’s in the Box

• 1 x Lower Unit Gear Oil Pump Assembly
• 1 x 3/8-16 Swivel Steel Adapter
• 1 x 8mm-1.25 Male x 3/8-16 Female Adapter
• 1 x 10mm-1.25 Male x 3/8-16 Female Adapter
• 1 x Long Suction Tube (6.125 inch/156 mm)
• 1 x Short Suction Tube (4.75 inch/121 mm)
• 1 x Clear Plastic Hose (19.5 inch/495 mm)

Installation Notes

1. Position the outboard or sterndrive in the vertical (down) position.
2. Place a suitable drain pan under the lower unit.
3. Slowly remove the upper (vent) and lower (drain/fill) plug screws. Inspect magnetic screw ends for metal debris.
4. Allow all of the old gear oil to drain completely. This may take several minutes.
5. Select the appropriate length suction tube for your oil bottle and securely attach the pump assembly.
6. Attach the correct adapter fitting (3/8-16, 8mm, or 10mm) for your engine to the end of the clear hose.
7. Firmly insert and thread the adapter into the lower drain plug hole.
8. Pump the new gear oil into the lower unit until you see fresh oil begin to flow out of the upper vent hole.
9. Reinstall the upper vent plug screw first, ensuring its washer is in good condition.
10. Quickly remove the pump adapter from the lower hole and reinstall the lower drain plug screw.
11. Tighten both plug screws to the manufacturer's recommended torque. Do not overtighten.
12. Properly dispose of the used gear oil according to local regulations.

Troubleshooting & FAQ

Safety & Important Info

• Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
• Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.