Lower Unit Gear Oil Pump – Fits Most Marine Outboard Motors (Multiple Adapters)
Lower Unit Gear Oil Pump – Fits Most Marine Outboard Motors (Multiple Adapters) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Lower Unit Gear Oil Pump – Fits Most Marine Outboard Motors (Multip...
Lower Unit Gear Oil Pump – Fits Most Marine Outboard Motors (Multiple Adapters) is backordered and will ship as soon as it is back in stock.
Product Details
This versatile Lower Unit Gear Oil Pump is designed for standard quart bottles and is compatible with most marine outboard motors. With multiple included adapters (3/8", 8mm, and 10mm), it provides a clean and efficient solution for changing gear oil in the lower units of engines from brands like Mercury, Mariner, Yamaha, Honda, and more.
This pump serves as a direct replacement for similar models, including the Slippery Pete, RETEPIF, and Bentolin lower unit gear oil pumps.
- Installs directly by threading onto standard quart bottles with a 28mm opening.
- Includes three metal adapters to fit the most common outboard engine drain plugs.
- Delivers a consistent flow of 8-10cc per pump stroke for a quick refill.
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury/Mariner models, use the 3/8" swivel adapter.
For Yamaha, Nissan, and Tohatsu models, use the 10mm-1.25 male adapter.
For Honda, Johnson, and Evinrude models, use the 8mm-1.25 male adapter.
| Brand | Model | Rated HP | Stroke | Years | Notes |
|---|---|---|---|---|---|
| Mercury/Mariner | Most outboard models | Various | 2-Stroke & 4-Stroke | All | 3/8" swivel adapter compatibility |
| Yamaha | Most outboard models | Various | 2-Stroke & 4-Stroke | All | 10mm-1.25 male adapter compatibility |
| Nissan | Most outboard models | Various | 2-Stroke & 4-Stroke | All | 10mm-1.25 male adapter compatibility |
| Tohatsu | Most outboard models | Various | 2-Stroke & 4-Stroke | All | 10mm-1.25 male adapter compatibility |
| Honda | Most outboard models | Various | 2-Stroke & 4-Stroke | All | 8mm-1.25 male adapter compatibility |
| Johnson/Evinrude | Most outboard models | Various | 2-Stroke & 4-Stroke | All | 8mm-1.25 male adapter compatibility |
| Volvo Penta | All models | Not compatible |
Technical Specs
- Product Type
- Lower Unit Gear Oil Pump
- Installation
- Direct thread onto standard quart bottles (28mm opening)
- Connection
- Multiple adapters: 3/8 inch metal swivel, 8mm and 10mm metal adapters
- Housing Material
- Plastic and aluminum
- Flow Rate
- 8-10cc per pump stroke
- Compatibility
- Most marine outboard motors (not compatible with Volvo Penta)
- Included Adapters
- 3/8" swivel adapter, 8mm male adapter, 10mm male adapter
- Hose Type
- Flexible discharge hose
- Bottle Compatibility
- Standard quart bottles with 28mm openings
- Application
- Lower unit gear oil refilling
What’s in the Box
- 1 x Lower Unit Gear Oil Pump
- 1 x 3/8" Metal Swivel Adapter
- 1 x 8mm Metal Adapter
- 1 x 10mm Metal Adapter
- 1 x Short Suction Tube
- 1 x Long Suction Tube
- 1 x Flexible Discharge Hose
Installation Notes
- Drain the old oil from your lower unit by removing both the upper and lower drain plugs.
- Select and attach the appropriate adapter to the pump based on your engine brand.
- Screw the pump assembly securely onto a standard quart bottle of new gear oil.
- Insert the adapter into the lower drain hole of your engine's lower unit.
- Pump new oil into the lower unit until it begins to flow smoothly out of the upper vent hole.
- Quickly replace and tighten the upper vent plug, then remove the pump and replace the lower drain plug.
Troubleshooting & FAQ
What engines is this pump compatible with?
This pump is designed for a wide range of outboard motors, including most models from Mercury, Mariner, Yamaha, Nissan, Tohatsu, Honda, and Johnson/Evinrude. It is not compatible with any Volvo Penta engines.
Which adapter should I use for my engine?
The pump comes with three adapters to fit different brands. Use the 3/8" swivel adapter for Mercury/Mariner, the 10mm adapter for Yamaha/Nissan/Tohatsu, and the 8mm adapter for Honda/Johnson/Evinrude models.
Will this pump fit any gear oil bottle?
It is designed to fit standard quart bottles that have a 28mm threaded opening, which is common for most marine gear oils.
How much oil does it move with each pump?
The pump dispenses approximately 8 to 10 cubic centimeters (cc) of oil with each full pump stroke, allowing for controlled and efficient filling.
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.
Payment & Security
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