Lower Unit Gear Oil Pump Kit with 3 Adapters for Outboard and Sterndrive Gearcase Oil Service
Lower Unit Gear Oil Pump Kit with 3 Adapters for Outboard and Sterndrive Gearcase Oil Service is backordered and will ship as soon as it is back in stock.
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Lower Unit Gear Oil Pump Kit with 3 Adapters for Outboard and Stern...
Lower Unit Gear Oil Pump Kit with 3 Adapters for Outboard and Sterndrive Gearcase Oil Service is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket marine Lower Unit Gear Oil Pump Kit helps fill or refill gearcase oil on compatible outboard and sterndrive lower units. The pump connects to standard 28 mm threaded quart gear-lube bottles and includes three adapter fittings for commonly used marine fill-port thread sizes.
Use the adapter that matches the fill port on your specific gearcase. Always compare the fitting, bottle thread, and service instructions for your engine before installation.
- Hand-operated pump transfers approximately 8–10 cc of fluid per full stroke for controlled filling.
- Includes a flexible 19.5-inch (495 mm) clear hose for reaching lower-unit fill ports.
- Includes 3/8-16, 8 mm-1.25, and 10 mm-1.25 metal adapters.
- Includes long and short suction tubes for use with different quart-bottle heights.
Reference Information
This pump kit is an aftermarket replacement-style service tool. Brand and model references below describe intended service applications; they do not replace confirmation of the correct fill-port thread for a particular engine or sterndrive.
| Brand or Family | Typical Application | Adapter Guidance |
|---|---|---|
| Mercury, Mariner, Force | Compatible outboard gearcases | 3/8-16 swivel adapter where applicable |
| MerCruiser | Compatible sterndrives | 3/8-16 swivel adapter where applicable |
| Johnson, Evinrude, OMC | Compatible outboard gearcases | Confirm the fill-port thread before use |
| Yamaha, Honda, Suzuki, Nissan, Tohatsu | Compatible outboard gearcases | Use the 8 mm or 10 mm adapter as required by the fill port |
Technical Specifications
- Product Type
- Lower unit gear oil pump kit
- Operation
- Hand-operated manual pump
- Intended Fluid
- Marine gear oil or gear lube; not for fuel
- Bottle Connection
- 28 mm standard quart-bottle threads
- Housing
- Plastic pump body with metal adapters
- Color
- Black and clear
- Hose Length
- 19.5 inches (495 mm)
- Pump Body Length
- Approximately 6 inches (152 mm)
- Approximate Weight
- 170 g (0.37 lb)
- Included Adapter Threads
- 3/8-16 swivel, 8 mm-1.25, and 10 mm-1.25
- Approximate Output
- 8–10 cc per full stroke
- Suction Tubes
- Long tube: 6.125 inches (156 mm); short tube: 4.75 inches (121 mm)
What's Included
- 1 x Lower unit gear oil pump assembly
- 1 x 3/8-16 swivel steel adapter
- 1 x 8 mm-1.25 male x 3/8-16 female adapter
- 1 x 10 mm-1.25 male x 3/8-16 female adapter
- 1 x Long suction tube, 6.125 inches (156 mm)
- 1 x Short suction tube, 4.75 inches (121 mm)
- 1 x Clear plastic hose, 19.5 inches (495 mm)
Installation Notes
- Place the outboard or sterndrive in the vertical position and support it securely.
- Position a suitable drain pan beneath the lower unit.
- Remove the upper vent plug and lower drain/fill plug carefully. Inspect the magnetic plug ends for metal debris.
- Allow the used gear oil to drain completely.
- Select the suction tube that reaches the bottom of the gear-oil bottle and attach the pump securely.
- Select the adapter that matches the lower-unit fill-port thread and connect it to the clear hose.
- Insert and thread the adapter into the lower drain/fill opening without cross-threading.
- Pump fresh gear oil into the lower unit until oil begins to flow from the upper vent opening, following the engine or sterndrive manufacturer's service procedure.
- Reinstall the upper vent plug with its serviceable washer.
- Remove the pump adapter from the lower opening and reinstall the lower drain plug promptly.
- Tighten both plugs to the manufacturer's specified torque. Do not overtighten.
- Dispose of used gear oil according to local regulations.
Troubleshooting & FAQ
Which adapter should I use?
Choose the adapter that matches the thread in your lower-unit fill port. The kit includes 3/8-16, 8 mm-1.25, and 10 mm-1.25 adapters. Do not force a fitting or use one that does not thread smoothly by hand.
Will this pump fit any quart bottle of gear lube?
The pump is designed for standard 28 mm threaded quart bottles. Bottle-neck dimensions and thread patterns can vary, so confirm compatibility before use. Non-standard bottle threads may not fit.
How much oil does the pump transfer per stroke?
Output is approximately 8–10 cc per full stroke. Actual output can vary with the fluid, seal, bottle, and pumping speed.
Why are two suction tubes included?
The long 6.125-inch and short 4.75-inch tubes accommodate different quart-bottle heights and help the pump reach the fluid.
The pump is not drawing oil. What should I check?
Confirm that the pump is fully tightened onto the bottle, the selected suction tube is fully submerged, the hose connections are secure, and the adapter is properly seated. Check for damaged seals or air leaks before continuing.
Is this an OEM pump?
No. This is an aftermarket replacement-style gear-oil pump kit. Confirm the adapter, bottle connection, and service procedure for your specific engine or sterndrive before use.
Safety & Important Information
- Verify the fill-port thread and bottle connection before purchase and installation.
- Do not use this pump for fuel, brake fluid, solvents, or other fluids outside its intended gear-oil application.
- Use only the correct adapter and avoid cross-threading aluminum or other soft components.
- Wear suitable gloves and eye protection when draining and filling gear oil.
- Follow the engine or sterndrive manufacturer's oil type, fill level, torque, and maintenance instructions.
- This is an aftermarket product, not an OEM component.
- Professional installation is recommended if you are uncertain about the correct fitting or service procedure.
About Sea Sierra
- Marine service products selected for practical maintenance and repair applications.
- Aftermarket solutions designed to help simplify routine gearcase oil service.
- Review the product specifications and compatibility details before ordering.
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