Lower Unit Gear Lube Oil Pump for Marine Gearcase Service — Replaces Mercury 26-830749 and 8M0204693
Lower Unit Gear Lube Oil Pump for Marine Gearcase Service — Replaces Mercury 26-830749 and 8M0204693 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Lower Unit Gear Lube Oil Pump for Marine Gearcase Service — Replace...
Lower Unit Gear Lube Oil Pump for Marine Gearcase Service — Replaces Mercury 26-830749 and 8M0204693 is backordered and will ship as soon as it is back in stock.
Product Details
This lower unit gear lube oil pump assembly is designed to help transfer marine gear lubricant during lower-unit and sterndrive service. It is intended for use with standard quart gear-lubricant bottles with a 28 mm threaded opening and includes adapters for several common drain and fill plug sizes.
The pump is marketed as an aftermarket replacement for Mercury references 26-830749 and 8M0204693. These references identify the replacement application and do not indicate that this product is a genuine Mercury component.
- Manual hand pump for controlled gear-lubricant transfer.
- Designed for standard quart bottles with a 28 mm opening.
- Includes 3/8-inch, 8 mm, and 10 mm metal adapters for common lower-unit service connections.
- Suitable for many marine applications when the bottle connection and drain-plug thread match.
Part Number References
Use the following manufacturer references when comparing replacement applications. Always confirm the connection size and original equipment requirements before ordering.
| Brand | Reference Number |
|---|---|
| Mercury | 26-830749 |
| Mercury | 8M0204693 |
| Mercury | 830749 |
Engine & Model Compatibility
This pump assembly is intended for many Mercury outboard and MerCruiser sterndrive service applications and may also be usable with other marine brands when the bottle opening and drain/fill connection match. The available product information does not establish a complete model-year, serial-number, horsepower, or stroke-specific fitment list.
Verify the thread or adapter size on your lower unit before purchase. Do not assume compatibility from the engine brand alone. Volvo Penta and other applications should be confirmed separately rather than assumed compatible.
| Brand or Application | Coverage | Verification Required | Reference Numbers |
|---|---|---|---|
| Mercury outboards | Many applications using the specified bottle and service connection | Confirm model and drain/fill thread | 26-830749, 8M0204693 |
| MerCruiser sterndrives | Many applications using the specified bottle and service connection | Confirm sterndrive model and drain/fill thread | 26-830749, 8M0204693 |
| Yamaha, Honda, Suzuki, and other marine applications | Potential use where dimensions and connection sizes match | Confirm application-specific requirements | Not separately verified |
Technical Specs
- Product Type
- Lower unit gear lube oil pump assembly
- Installation
- Manual hand pump
- Bottle Connection
- Designed for standard quart bottles with a 28 mm opening
- Housing Material
- Plastic pump housing with metal adapters
- Housing Color
- White or clear housing with metal adapters; appearance may vary
- Fitting Options
- 3/8-inch swivel, 8 mm, and 10 mm adapters
- Output
- Approximately 8 cc per stroke where applicable to the pump configuration
- Intended Fluid
- Marine lower-unit gear lubricant
What’s in the Box
This listing is for one pump assembly with the accessories listed below. It is not a genuine Mercury-branded component.
- 1 x Lower unit gear lube oil pump assembly
- 1 x 3/8-inch swivel adapter
- 1 x 8 mm metal adapter
- 1 x 10 mm metal adapter
- 2 x Rigid suction tubes, approximately 13 cm and 15 cm
- 1 x Cap adapter for a 28 mm bottle opening
- 1 x Flexible clear fill tube
- 2 x Drain gaskets for applicable Mercury and MerCruiser service applications
Installation Notes
- Place a suitable drain pan under the lower unit or sterndrive.
- Remove the lower drain/fill screw and the upper vent screw from the gearcase.
- Allow the old gear lubricant to drain completely. Inspect it for metal particles or a milky appearance.
- Identify the correct adapter by comparing it with the lower-unit drain/fill opening. Do not force an adapter into the threads.
- Attach the pump assembly to a fresh bottle of the manufacturer-recommended lower-unit gear lubricant.
- Connect the flexible fill tube to the selected adapter and install the adapter securely in the lower opening.
- Pump lubricant into the gearcase until a steady flow reaches the upper vent opening, following the engine manufacturer’s service procedure.
- Keep the system filled while reinstalling the upper vent screw to minimize fluid loss.
- Remove the fill tube and lower adapter, then reinstall the lower drain/fill screw promptly.
- Tighten both screws to the manufacturer’s specified torque. Do not overtighten.
- Clean excess lubricant from the gearcase and dispose of used oil according to local requirements.
Troubleshooting & FAQ
Will this pump fit my specific engine?
The pump is intended for many Mercury and MerCruiser applications and may work on other marine brands when the bottle opening and service connection match. A complete model-year and serial-number fitment list is not available. Verify your lower-unit drain/fill thread and bottle connection before purchase.
How do I know which adapter to use?
Compare the supplied 3/8-inch, 8 mm, and 10 mm adapters with the lower-unit drain/fill opening. Test-fit the correct adapter by hand before attaching the pump. It should engage smoothly without cross-threading or excessive force.
The pump is not drawing lubricant from the bottle. What should I check?
Make sure the suction tube is fully submerged and securely attached. Confirm that the cap adapter is tightened enough to create an air seal, and check the tube, cap, and pump housing for cracks or air leaks. Thick lubricant may require steady, full pump strokes.
What is the difference between this pump and an OEM version?
This is an aftermarket replacement pump, not a genuine Mercury component. The listed Mercury numbers are replacement references. Confirm dimensions, adapter size, and service requirements against the original application before installation.
How much lubricant does the pump move per stroke?
The available product information rates the pump at approximately 8 cubic centimeters per stroke where applicable. Actual flow can vary with lubricant viscosity, tube length, bottle position, and seal quality.
Can this pump be used for other fluids such as engine oil?
It is intended for marine lower-unit gear lubricant. Do not use it with gasoline, solvents, corrosive chemicals, or other volatile fluids. Avoid cross-contamination by using clean equipment and following the lubricant manufacturer’s instructions.
Is this product OEM?
No. This listing is for an aftermarket replacement pump assembly. It is not manufactured or branded by Mercury, MerCruiser, Yamaha, Honda, Suzuki, or Volvo Penta.
How quickly will my order ship?
Shipping options, delivery estimates, and costs are shown at checkout and may vary by destination, inventory, and service level.
What are the warranty and return terms?
Warranty coverage and return eligibility are governed by the applicable store policy. Keep the order information and contact support before returning a product if the pump arrives damaged or does not match the listed contents.
Safety & Important Information
- Verify the bottle opening, adapter size, and lower-unit service procedure before use.
- Use only the lubricant specified by the engine or sterndrive manufacturer.
- Do not force mismatched threads or adapters, and do not overtighten drain screws.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended when the correct service procedure or lubricant specification is uncertain.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for practical service applications.
- Global Fulfillment — Shipping availability and delivery estimates are presented at checkout.
- Manufacturer-Direct Value — We focus on useful replacement products and clear application information.
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