Marine Lower Unit Gear Lube Oil Pump – Fits Standard Quart Bottles with 28mm Caps (Replaces Multiple OEM Adaptors)

Marine Lower Unit Gear Lube Oil Pump – Fits Standard Quart Bottles with 28mm Caps

This manual hand pump is designed to efficiently transfer gear oil to the lower units of outboard motors and stern drives. It fits standard quart bottles with 28mm caps and features multiple interchangeable adaptors for broad compatibility across major marine engine brands.

It suits a variety of Mercury and Mercruiser outboard motors and sterndrives requiring a 3/8" swivel adaptor, as well as foreign outboards like Yamaha, Honda, Suzuki, Nissan, and Tohatsu that use 8mm or 10mm threaded fill ports.

• Includes multiple adaptors: 3/8" swivel, 8mm, 10mm for foreign and domestic outboards
• Manual hand pump: easy to operate and install
• Gear oil only: designed specifically for lower unit gear lube transfer

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Fluid Pump with 28mm Bottle Cap Adaptor
• 1 x 3/8" Swivel Adapter
• 1 x 8mm Metal Adapter (8mm-1.25 male x 3/8"-16 female)
• 1 x 10mm Metal Adapter (10mm-1.25 male x 3/8"-16 female)
• 2 x Rigid Suction Tubes (13cm, 15cm) for different bottle heights
• 1 x Flexible Clear Fill Tube (19.5 inch/495mm)
• 2 x Oil Drain Plug Gaskets (for Mercury outboards, 830749)

Installation Guide

1. Remove the original gear oil bottle cap from your quart bottle.
2. Attach the pump using the 28mm bottle cap adaptor securely onto the bottle.
3. Select the appropriate adaptor (3/8" swivel, 8mm, or 10mm) for your engine fill port.
4. Connect the flexible clear fill tube and/or rigid suction tubes as needed to match the bottle height.
5. Insert the adaptor into the engine lower unit fill port.
6. Operate the manual hand pump to transfer the gear oil until the lower unit is filled appropriately.
7. Remove the pump assembly and re-install the original fill port cap securely.
8. Check for leaks and ensure proper fit before operating the engine.

Troubleshooting & FAQ

Q: How do I confirm this fits my engine?
A: Review the compatible engine models table and compare your engine’s model and fill port size. Use manufacturer guides linked above for serial/model verification.

Q: What if my engine uses a non-standard fill port size?
A: This pump includes adaptors specifically for 3/8" swivel, 8mm, and 10mm ports. If your engine uses a different size, this pump may not be compatible.

Q: How often should I replace the pump or adapters?
A: Regular inspection and replacement are recommended if you notice wear, leaks, or reduced pumping efficiency.

Q: What are common signs the pump is failing?
A: Difficulty pumping, leaks around connections, or failure to transfer oil indicate replacement is needed.

Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.