Marine Lower Unit Gear Lube Oil Pump for Standard Quart Bottles with 28 mm Caps
Marine Lower Unit Gear Lube Oil Pump for Standard Quart Bottles with 28 mm Caps 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.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Marine Lower Unit Gear Lube Oil Pump for Standard Quart Bottles wit...
Marine Lower Unit Gear Lube Oil Pump for Standard Quart Bottles with 28 mm Caps is backordered and will ship as soon as it is back in stock.
Product Details
This Marine Lower Unit Gear Lube Oil Pump is designed to transfer gear oil into the lower units of outboard motors and stern drives. The pump attaches to standard quart-size gear lube bottles with 28 mm caps and uses interchangeable fill adapters to accommodate several commonly used lower-unit fill-port thread sizes.
The included adapters provide a convenient alternative to purchasing separate brand-specific filling tools. Adapter fitment depends on the thread size and configuration of the fill port on the particular engine or sterndrive, so confirm the original fitting before use.
- Manual hand-pump operation for controlled gear-oil filling.
- Includes interchangeable metal fill adapters and two suction-tube sizes.
- Intended for transferring lower-unit gear oil; do not use it for fuel, solvents, brake fluid, or other incompatible liquids.
Adapter Reference
The following adapter sizes are included as general fitment references. They are not a confirmation of compatibility with every engine model or year.
| Adapter | Typical application reference | Important note |
|---|---|---|
| 3/8 in swivel adapter | Commonly used on many US-market outboards and sterndrives | Confirm the lower-unit fill-port thread before installation. |
| 8 mm adapter | Used on some metric lower-unit fill ports | Thread and seal configuration must match the engine. |
| 10 mm adapter | Used on some metric lower-unit fill ports | Thread and seal configuration must match the engine. |
Brand names and product references may help identify the required fitting, but they do not by themselves establish fitment. Always compare the included adapter with the original fill screw and verify the thread size.
Compatibility Guidance
This pump is intended for lower-unit gear-oil service on compatible outboard motors and stern drives that use one of the included adapter configurations. It may be suitable for applications from brands such as Mercury, MerCruiser, Yamaha, Honda, Suzuki, Nissan, Tohatsu, Johnson, and Evinrude when the fill-port thread matches an included adapter.
Compatibility is determined by the fill-port fitting, not solely by the engine brand, horsepower, stroke, model, or year. Some applications require a different adapter and are not confirmed by this listing. Volvo Penta sterndrives are not confirmed compatible with the included adapters.
| Application group | Adapter reference | Fitment condition |
|---|---|---|
| Many US-market outboards and sterndrives | 3/8 in swivel adapter | Use only when the lower-unit fill port matches the adapter thread. |
| Some metric outboard applications | 8 mm or 10 mm adapter | Select the adapter that matches the original fill-port thread. |
| Applications requiring another fitting | Not confirmed | A separate adapter may be required. |
| Volvo Penta sterndrives | Not confirmed | Do not assume compatibility; a different adapter may be required. |
Before ordering or installing: compare the adapter dimensions with the original lower-unit fill fitting and verify the application-specific service instructions.
Technical Specs
- Product Type
- Lower Unit Gear Oil Transfer Pump
- Installation
- Manual hand pump
- Pump Capacity
- Approximately 8–10 cc per pump stroke
- Bottle Connection
- 28 mm bottle-cap adapter for compatible standard quart gear-lube bottles
- Included Fitting Sizes
- 3/8 in swivel, 8 mm, and 10 mm adapters
- Thread References
- 3/8 in-16, 8 mm-1.25, and 10 mm-1.25 as applicable to the included adapters
- Hose Length
- Approximately 19.5 in (495 mm)
- Rigid Tube Lengths
- Approximately 13 cm and 15 cm
- Approximate Weight
- 4 oz (113 g)
- Materials
- Plastic, rubber, steel, and aluminum-alloy components
- Color
- Black and gray
What's in the Box
- 1 × fluid pump with 28 mm bottle-cap adapter
- 1 × 3/8 in swivel adapter
- 1 × 8 mm metal adapter
- 1 × 10 mm metal adapter
- 2 × rigid suction tubes, approximately 13 cm and 15 cm
- 1 × flexible clear fill tube, approximately 19.5 in (495 mm)
- 2 × oil drain-plug gaskets for applicable Mercury applications
Package contents are limited to the components listed above. The pump is an aftermarket service tool and is not an OEM component.
Installation Notes
- Select the rigid suction tube that best suits the gear-lube bottle and attach it securely to the pump base.
- Attach the pump to a compatible standard quart bottle with a 28 mm cap and ensure the connection is sealed.
- Confirm the lower-unit fill-port thread and select the matching 3/8 in, 8 mm, or 10 mm adapter.
- Connect the selected adapter to the flexible clear fill tube.
- Place a suitable drain pan below the lower unit and remove the upper vent and lower fill screws according to the engine manufacturer's service procedure.
- Allow the old gear oil to drain completely.
- Insert the selected fill adapter into the lower fill opening and keep the connection secure.
- Pump new gear lube into the gear case until it reaches the level specified by the engine or sterndrive manufacturer.
- Reinstall the upper vent screw as directed by the service procedure.
- Remove the fill adapter and reinstall the lower fill screw promptly to minimize fluid loss.
- Tighten the screws to the manufacturer's specified torque, wipe the area clean, and check for leaks.
Use only the correct lubricant and follow the service instructions for the specific engine or sterndrive. Do not rely on the adapter fit alone to determine the correct fluid level or tightening torque.
Troubleshooting & FAQ
Which adapter should I use?
Select the adapter that matches the thread and sealing arrangement of the lower-unit fill port. The 3/8 in swivel adapter is commonly used on many US-market applications, while the 8 mm and 10 mm adapters are intended for compatible metric applications. Verify the fitting before use.
Is this pump compatible with every Mercury, MerCruiser, Yamaha, Honda, or Suzuki model?
No. Brand and model alone do not confirm compatibility. The lower-unit fill-port thread must match one of the included adapters, and some model, year, or sterndrive applications may require a different fitting.
Is it compatible with Volvo Penta sterndrives?
Compatibility with Volvo Penta sterndrives is not confirmed. These applications may require a different adapter that is not included.
The pump is not drawing oil from the bottle. What should I check?
Check that the suction tube is firmly attached and reaches the bottom of the bottle. Make sure the bottle connection is tight enough to create a seal and confirm that the hose and adapter connections are secure. Inspect the pump and tubing for blockage or damage.
How much fluid does the pump move per stroke?
The pump moves approximately 8–10 cc per full stroke. Actual output can vary with the lubricant viscosity, bottle position, hose routing, and the condition of the pump seal.
Is this an OEM component?
No. This is an aftermarket gear-lube transfer pump intended to provide a practical service-tool alternative when the included adapter matches the application.
What fluids can be used with the pump?
Use it only for compatible marine gear oil or gear lubricant. Do not use it with fuel, solvents, brake fluid, or other fluids that may damage the pump or create a safety hazard.
Shipping speed and cost?
Typical transit is 5–15 days, with standard shipping offered free where available. Expedited options, delivery estimates, and destination restrictions are shown at checkout.
Warranty and returns?
This product is covered by a 1-year warranty against manufacturing defects under normal use. Returns are accepted within the applicable standard return window when the item is unused and in original condition. Refer to the current store policy for complete terms.
Safety & Important Information
- Verify the adapter, thread size, and sealing arrangement against the original lower-unit fitting before use.
- Keep the pump, hose, and adapters clean to avoid contaminating the gear case.
- Follow the engine or sterndrive manufacturer's lubricant, level, torque, and service instructions.
- Wear appropriate eye protection and collect used lubricant in a suitable container.
- This is an aftermarket service tool, not an OEM component.
- Professional installation is recommended when the correct fitting or service procedure is uncertain.
About Sea Sierra
- Pro-Grade Standards — Marine service tools selected for practical maintenance applications.
- Fast Global Fulfillment — Standard delivery is available to most regions, subject to destination and checkout options.
- Manufacturer-Direct Value — Practical aftermarket equipment at a competitive value.
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