Tilt End Cap & Seals – Fits Mercury 75-250HP Outboard (Replaces 878239A02, 811606, 878239A1)
Tilt End Cap & Seals – Fits Mercury 75-250HP Outboard (Replaces 878239A02, 811606, 878239A1) 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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Tilt End Cap & Seals – Fits Mercury 75-250HP Outboard (Replaces...
Tilt End Cap & Seals – Fits Mercury 75-250HP Outboard (Replaces 878239A02, 811606, 878239A1) is backordered and will ship as soon as it is back in stock.
Product Details
This replacement Tilt End Cap & Seals assembly is designed for Mercury Marine 75-250HP 2-stroke and 4-stroke V6 outboard engines from 1991–2017, including Optimax, EFI, and carbureted models. It provides a durable, reliable solution for repairing leaking or damaged tilt cylinders.
It serves as a direct interchange for Mercury part numbers 878239A02, 878239A1, 811606, and 8M0090322, among other aftermarket equivalents.
- Engineered as a direct-fit replacement for straightforward installation.
- Constructed from aircraft-grade aluminum with a hard anodized coating for superior corrosion resistance.
- Includes high-grade Viton and urethane seals to ensure a long-lasting, leak-free repair.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 878239A02 |
| Mercury | 878239A1 |
| Mercury | 811606 |
| Mercury | 8M0090322 |
| SAIL MARINE | 878239A02 |
| Five Star Marine | FSM042 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits a wide range of Mercury V6 (Generation 2 & 3) outboards, including Optimax, EFI, and carbureted models. Also compatible with select 4-stroke applications, but does not fit L6 Verado engines.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | V6 Gen 2 & 3 | 135 | 2-Stroke | 1991–2017 | 878239A02/878239A1/811606 | Optimax/EFI/Carb |
| Mercury | V6 Gen 2 & 3 | 150 | 2-Stroke | 1991–2017 | 878239A02/878239A1/811606 | Optimax/EFI/Carb |
| Mercury | V6 Gen 2 & 3 | 175 | 2-Stroke | 1991–2017 | 878239A02/878239A1/811606 | Optimax/EFI/Carb |
| Mercury | V6 Gen 2 & 3 | 200 | 2-Stroke | 1991–2017 | 878239A02/878239A1/811606 | Optimax/EFI/Carb |
| Mercury | V6 Gen 2 & 3 | 225 | 2-Stroke | 1991–2017 | 878239A02/878239A1/811606 | Optimax/EFI/Carb |
| Mercury | V6 Gen 2 & 3 | 250 | 2-Stroke | 1991–2017 | 878239A02/878239A1/811606 | Optimax/EFI/Carb |
| Mercury | V6 Gen 2 & 3 | 300 | 2-Stroke | 1991–2017 | 878239A02/878239A1/811606 | Optimax/EFI/Carb |
| Mercury | 4-Stroke | 135-200 | 4-Stroke | 878239A02/878239A1/811606 | Does NOT fit L6 Verado |
Technical Specs
- Product Type
- Tilt Cylinder End Cap with Seals
- Installation
- Direct replacement
- Connection
- Tilt Ram/Cylinder
- Housing Material
- Aircraft Grade Aluminum with Hard Anodized Coating
- Housing Color
- Black
- Fitting Type
- Tilt Ram End Cap/Gland
- Warranty
- 1-2 years (varies by manufacturer)
- Other Technical Attributes
- Military Grade Type 3 Hard Coat Anodized; Viton/High Grade Urethane Seals
What’s in the Box
- 1 x Tilt End Cap with Seals (878239A02/878239A1/811606/8M0090322)
Installation Notes
- Safely support the outboard motor in the fully tilted position using a motor support bracket.
- Relieve any hydraulic pressure in the system according to your service manual.
- Place a drain pan under the tilt cylinder to catch hydraulic fluid.
- Using a compatible spanner wrench, carefully unscrew and remove the old tilt end cap.
- Remove the old seals from the cylinder bore and ram, being careful not to scratch any surfaces.
- Clean the cylinder and ram thoroughly.
- Lubricate the new seals with fresh hydraulic fluid and install them onto the new end cap and into the cylinder as required.
- Carefully thread the new end cap into the cylinder and tighten to the manufacturer's specified torque.
- Refill the trim/tilt reservoir with the recommended hydraulic fluid and bleed the system of air by cycling the tilt and trim function several times.
- Check for leaks and top off the fluid level as needed.
Troubleshooting & FAQ
Will this fit my Mercury Verado engine?
No, this end cap is specifically not compatible with L6 Verado models. It is designed for V6 Gen 2 & 3 and specific 4-stroke models within the specified horsepower range.
How can I tell if my current end cap is failing?
The most common signs of a failing tilt end cap are hydraulic fluid leaks around the tilt ram, a "spongy" or drifting trim/tilt system that won't hold its position, or visible bubbling, corrosion, and physical damage on the cap itself.
What is the main difference between this part and the OEM version?
This is an aftermarket part built to meet or exceed OEM specifications. It is constructed from high-strength, aircraft-grade aluminum with a military-grade Type 3 hard anodized coating for enhanced durability and corrosion resistance. The included seals are made from high-grade Viton and urethane for optimal performance and longevity.
What tools are needed to install this part?
Installation requires a specific spanner wrench designed for marine tilt and trim caps to safely remove the old cap and tighten the new one. You will also need basic mechanic's tools, a drain pan, and a secure way to support the outboard motor.
Is it necessary to replace the seals when replacing the cap?
Yes. This kit includes all the necessary seals, and they should always be replaced when installing a new end cap to ensure a proper, leak-proof fit and prevent premature failure.
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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