Lower Unit Gear Lube Oil Pump – Fits Mercury/Mercruiser, Yamaha, Honda, Suzuki (Replaces Multiple OEM Adaptors)

$12.99 $20.00

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Lower Unit Gear Lube Oil Pump – Fits Mercury/Mercruiser, Yamaha, Honda, Suzuki (Replaces Multiple OEM Adaptors) is backordered and will ship as soon as it is back in stock.

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Product Details

This Marine Lower Unit Gear Lube Oil Pump is designed to cleanly and efficiently transfer gear oil into the lower units of most outboard motors and stern drives. The pump fits directly onto standard quart bottles with 28mm caps and comes with a set of interchangeable adapters for broad compatibility with major marine engine brands.

The included adapters allow this single pump to replace multiple OEM-specific tools, providing equivalents for Mercury/Mercruiser (3/8"-16), Yamaha, Honda, Suzuki, and other foreign outboards (8mm/10mm).

Features a simple, manual hand-pump operation with a delivery volume of 8-10cc per stroke for precise filling.
Includes three metal fill port adapters and two suction tube sizes to fit different bottle heights and engine types.
Engineered for use with gear oil only.

Part Number Matrix

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

Brand	Part Number	Notes
Mercury / Mercruiser	830749	Gasket part number
Mercury / Mercruiser	8M0204693	Adapter part number reference

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This pump fits most Mercury, Mercruiser, and other US-made outboards or sterndrives using the included 3/8"-16 swivel adapter. Some Johnson/Evinrude models may require a different adapter.

It is also compatible with most foreign outboard models from brands like Yamaha, Honda, Suzuki, Nissan, and Tohatsu using the 8mm or 10mm threaded adapters.

Brand	Model	Rated HP	Stroke	OEM Part No.	Notes
Mercury	F30-F400 Series	30-400	4-Stroke	830749, 8M0204693	3/8" adaptor
Mercury	D75-D300 Series	75-300	4-Stroke	830749, 8M0204693	3/8" adaptor
Mercury	E150-E250 Series	150-250	4-Stroke	830749, 8M0204693	3/8" adaptor
Mercruiser	Alpha/Bravo Sterndrives	Various	4-Stroke	830749, 8M0204693	3/8" adaptor
Yamaha	Most outboards	Various	2 & 4-Stroke		8mm or 10mm adaptor
Honda	Most outboards	Various	4-Stroke		8mm or 10mm adaptor
Suzuki	Most outboards	Various	4-Stroke		8mm or 10mm adaptor
Nissan/Tohatsu	Most outboards	Various	2 & 4-Stroke		8mm or 10mm adaptor
Johnson/Evinrude	Many models	Various	2 & 4-Stroke		Specific applications need verification

Note: This pump is not compatible with Volvo Penta sterndrives.

Technical Specs

Product Type: Lower Unit Gear Oil Transfer Pump
Installation: Manual hand pump
Pump Capacity: 8-10cc per pump stroke
Connection: 28mm bottle cap adaptor with interchangeable fill port adaptors
Fitting Type: Multiple adaptors: 3/8" swivel, 8mm, 10mm
Thread Size: 3/8"-16 (US outboards), 8mm-1.25, 10mm-1.25 (foreign outboards)
Hose Length: ~19.5 inch (495 mm)
Weight: ~4 ounces (113 g)
Housing Material: High-quality plastic, rubber, steel and aluminum alloy components
Housing Color: Black/Grey

What’s in the Box

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)
1 x Flexible Clear Fill Tube (19.5 inch/495mm)
2 x Oil Drain Plug Gaskets (for Mercury outboards, 830749)

Installation Notes

Select the correct rigid suction tube for your gear lube bottle and attach it firmly to the pump base.
Screw the pump securely onto the standard quart gear lube bottle (28mm cap).
Choose the appropriate adapter for your engine's lower unit: 3/8" for Mercury/Mercruiser, or 8mm/10mm for most foreign brands.
Attach the adapter to the flexible clear fill tube.
Position a drain pan under the lower unit and remove both the upper vent and lower fill screws.
Allow all old gear oil to drain completely.
Insert the fill tube with adapter into the lower drain screw hole.
Pump new lube into the gear case until fluid begins to flow out of the upper vent hole, which indicates it is full.
Re-install the upper vent screw plug first.
Quickly remove the fill tube and re-install the lower drain screw plug.
Tighten both plugs to the manufacturer's specified torque and wipe the area clean. Check for leaks after a short period.

Troubleshooting & FAQ

Which adapter do I use for my engine?

Use the 3/8"-16 swivel adapter for most Mercury, Mercruiser, and other US-made outboards. Use the 8mm or 10mm adapters for most Yamaha, Honda, Suzuki, Nissan, and Tohatsu models. Always check your engine's fill plug thread size to confirm.

Is this pump compatible with Volvo Penta sterndrives?

No, this pump kit is generally not compatible with Volvo Penta sterndrives, which often require a different type of adapter not included in this kit.

The pump isn't drawing oil from the bottle. What's wrong?

Ensure the suction tube is firmly attached and reaches the bottom of the bottle. Check that the pump is screwed tightly onto the bottle to create a proper seal. Also, make sure all connections, including the hose and adapters, are secure and hand-tightened.

What are the included gaskets for?

The kit includes two oil drain plug gaskets specifically for Mercury and Mercruiser outboards (replaces OEM part 830749), providing a fresh seal for your gear lube change.

How much fluid is transferred with each pump?

The pump delivers approximately 8-10cc of fluid per full stroke, allowing for controlled and efficient filling without waste.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

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.

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