O-Ring / Seal B for Oriented Bushing – Fits Mercury, Parsun 4-6 HP (Replaces 161771, PAT5-03000022)
O-Ring / Seal B for Oriented Bushing – Fits Mercury, Parsun 4-6 HP (Replaces 161771, PAT5-03000022) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
O-Ring / Seal B for Oriented Bushing – Fits Mercury, Parsun 4-6 HP ...
Product Details
This O-Ring / Seal B for Oriented Bushing is engineered to create a reliable seal, preventing oil and water leaks at the shift rod bushing interface. It is specifically designed for Mercury Marine 4-5 HP 2-stroke (1987–1989) and 4-6 HP 4-stroke outboards, along with Parsun 4-6 HP models that use an oriented bushing.
This part serves as a direct interchange for Mercury part numbers 161771 and 16177, Parsun PAT5-03000022, and GLM Marine 45350.
- Installation: Press fit into the oriented bushing.
- Material: Made from a durable rubber/synthetic material resistant to oil and salt water.
- Purpose: Prevents critical oil and water leaks at the shift rod bushing interface.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 161771 |
| Mercury | 16177 |
| Parsun | PAT5-03000022 |
| GLM Marine | 45350 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fitment includes select Mercury 4 HP and 5 HP 2-stroke models from 1987 to 1989.
Compatible with certain Parsun F4, F5, and F6 4-stroke outboard models (verify your part number, as year ranges are not provided for all models).
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 4 M | 4 | 2-Stroke | 1987 | 161771 | Fits model 1004207 |
| Mercury | 4 MH | 4 | 2-Stroke | 1988–1989 | 161771 | Fits models 1004201BK, 1004201GK |
| Mercury | 4 ML | 4 | 2-Stroke | 1987 | 161771 | Fits models 1004137, 1004227 |
| Mercury | 4 MLH | 4 | 2-Stroke | 1988–1989 | 161771 | Fits models 1004211BK, 1004216BK, 1004211GK, 1004216GK |
| Mercury | 5 MH | 5 | 2-Stroke | 1988–1989 | 161771 | Fits models 1005201BK, 1005201GK |
| Mercury | 5 MLH | 5 | 2-Stroke | 1988–1989 | 161771 | Fits models 1005211BK, 1005211GK |
Technical Specs
- Product Type
- O-Ring / Seal
- Installation
- Press fit into oriented bushing
- Housing Material
- Rubber/synthetic material resistant to oil and salt water
- Housing Color
- Black
- Dimensions
- 0.2 H x 7.0 W x 10.0 L cm
- Weight
- 0.01 kg (10 g)
- Fitting Type
- Oriented bushing seal
- Primary Function
- Prevents oil and water leaks at shift rod bushing interface
What’s in the Box
- 1 x O-Ring / Seal B for Oriented Bushing (161771/PAT5-03000022)
Installation Notes
- Ensure the engine is off and the kill switch lanyard is disconnected.
- Access the shift rod and oriented bushing area, removing any necessary covers or lower unit components.
- Carefully remove the old, worn o-ring from the bushing using a small pick or hook. Avoid scratching the metal surfaces.
- Thoroughly clean the bushing groove and surrounding area to remove any old sealant, debris, oil, or salt residue.
- Lightly lubricate the new o-ring with a marine-grade grease compatible with the housing material.
- Gently press the new seal into the bushing groove, ensuring it is seated evenly and is not twisted or pinched.
- Reassemble all components in the reverse order of disassembly, torquing fasteners to manufacturer specifications.
- After reassembly, manually check for proper shift linkage operation before starting the engine.
Troubleshooting & FAQ
How do I confirm this o-ring fits my engine?
This seal is designed for specific Mercury (4-6 HP, 1987-1989) and Parsun (4-6 HP) models. The most reliable method is to cross-reference your engine's model and year in the "Engine & Model Compatibility" table. Also, compare the part numbers listed in the "Part Number Matrix" to your service manual.
What are the signs of a failing bushing seal?
The most common signs are visible oil or water leaks around the shift rod where it enters the gearcase, an oily sheen on the water trailing your outboard, or water contamination in your lower unit oil (milky appearance).
How often should this seal be replaced?
We recommend inspecting the seal during any regular lower unit service and replacing it preventatively every 1-2 years, especially if operating in saltwater. Replace it immediately if you notice any signs of leaking, cracking, or hardening.
Is this part identical to the OEM Mercury part?
This is a high-quality aftermarket part engineered to meet or exceed OEM specifications for fit, form, and function. It is made from materials chosen for their durability in the marine environment, offering comparable performance to the original.
Do I need special tools for installation?
No proprietary tools are needed. Installation is a press-fit process. Accessing the bushing may require standard mechanic's tools to remove the lower unit, and a small, non-marring pick is helpful for removing the old seal.
My engine is listed, but my old part looks slightly different. What should I do?
Do not install the part. Manufacturers sometimes make mid-year changes. Please contact us with photos of your old part and any identifying numbers so we can help you confirm the correct fitment before you proceed.
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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