Tilt End Cap & Seals for Mercury 75–250 HP Outboards – Replaces 878239A02, 811606 and 878239A1
Tilt End Cap & Seals for Mercury 75–250 HP Outboards – Replaces 878239A02, 811606 and 878239A1 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.
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Tilt End Cap & Seals for Mercury 75–250 HP Outboards – Replaces...
Tilt End Cap & Seals for Mercury 75–250 HP Outboards – Replaces 878239A02, 811606 and 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 selected Mercury Marine 75–250 HP outboard applications, including V6 Gen 2 and Gen 3 models and selected Optimax, EFI, carbureted and 4-stroke applications. It is intended to replace a leaking or damaged tilt-cylinder end cap and restore a properly sealed hydraulic system.
This aftermarket replacement is listed as an interchange for Mercury part numbers 878239A02, 878239A1 and 811606. Confirm the original end-cap design, engine model, year and serial number before ordering.
- Replacement tilt-cylinder end cap with matching seals.
- Designed for direct replacement on compatible applications.
- Aircraft-grade aluminum housing with a hard-anodized coating for corrosion resistance.
- High-grade Viton and urethane seals for dependable hydraulic sealing.
Part Number Matrix
Use the following references to compare the listed OEM numbers with the replacement assembly.
| Brand | Part Number |
|---|---|
| Mercury | 878239A02 |
| Mercury | 878239A1 |
| Mercury | 811606 |
Engine & Model Compatibility
Compatibility depends on the exact tilt-cylinder design. Check the engine model, year, serial number and the original end cap before installation. The following applications are represented in the current product information and should be treated as fitment guidance rather than a substitute for an exact part-number comparison.
| Brand | Model / Configuration | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | V6 Gen 2 & Gen 3 | 135 | 2-Stroke | 1991–2017 | 878239A02 / 878239A1 / 811606 | Optimax, EFI or carbureted applications |
| Mercury | V6 Gen 2 & Gen 3 | 150 | 2-Stroke | 1991–2017 | 878239A02 / 878239A1 / 811606 | Optimax, EFI or carbureted applications |
| Mercury | V6 Gen 2 & Gen 3 | 175 | 2-Stroke | 1991–2017 | 878239A02 / 878239A1 / 811606 | Optimax, EFI or carbureted applications |
| Mercury | V6 Gen 2 & Gen 3 | 200 | 2-Stroke | 1991–2017 | 878239A02 / 878239A1 / 811606 | Optimax, EFI or carbureted applications |
| Mercury | V6 Gen 2 & Gen 3 | 225 | 2-Stroke | 1991–2017 | 878239A02 / 878239A1 / 811606 | Optimax, EFI or carbureted applications |
| Mercury | V6 Gen 2 & Gen 3 | 250 | 2-Stroke | 1991–2017 | 878239A02 / 878239A1 / 811606 | Optimax, EFI or carbureted applications |
| Mercury | Selected 4-stroke applications | 135–200 | 4-Stroke | Verify by model and serial number | 878239A02 / 878239A1 / 811606 | Not for L6 Verado applications |
Exclusion: This assembly is not compatible with L6 Verado engines. Because Mercury used multiple tilt-cylinder designs, always compare the original part before purchase.
Technical Specs
- Product Type
- Tilt-cylinder end cap with seals
- Installation
- Direct replacement on compatible applications
- Connection
- Tilt ram / hydraulic cylinder
- Housing Material
- Aircraft-grade aluminum with hard-anodized coating
- Housing Color
- Black
- Fitting Type
- Tilt-ram end cap / gland
- Seal Materials
- Viton and high-grade urethane
- Other Technical Attributes
- Type 3 hard-coat anodized housing and replacement hydraulic seals
- Warranty
- Refer to the applicable product warranty terms
What’s in the Box
- 1 × Tilt end cap with seals
Installation Notes
- Safely support the outboard motor in the fully tilted position with an appropriate motor-support bracket.
- Relieve hydraulic pressure according to the applicable service manual.
- Place a drain pan beneath the tilt cylinder to collect hydraulic fluid.
- Use a compatible spanner wrench to carefully remove the original tilt end cap.
- Remove the old seals from the cylinder bore and ram without scratching the sealing surfaces.
- Clean the cylinder and ram thoroughly and inspect them for scoring, corrosion or damage.
- Lubricate the replacement seals with fresh, compatible hydraulic fluid and install them in the correct positions.
- Carefully thread the replacement end cap into the cylinder and tighten it to the service-manual specification.
- Refill the trim/tilt reservoir with the recommended hydraulic fluid.
- Cycle the tilt and trim system several times to bleed air, then inspect for leaks and correct the fluid level as needed.
Troubleshooting & FAQ
Will this fit my Mercury Verado engine?
No. This listing is specifically not for L6 Verado models. Confirm the exact model, serial number and original end-cap part number before ordering.
How can I tell if my tilt end cap is failing?
Common symptoms include hydraulic-fluid leakage around the tilt ram, a spongy or drifting tilt/trim system, failure to hold position, or visible corrosion and physical damage around the end cap.
Is this an OEM part?
No. This is an aftermarket replacement intended to correspond to the listed Mercury part numbers. It is not manufactured or branded by Mercury Marine.
What tools are needed for installation?
Installation normally requires a marine tilt-and-trim end-cap spanner wrench, basic mechanic’s tools, a drain pan and a secure method of supporting the outboard. Follow the applicable service manual for removal, torque and bleeding procedures.
Should the seals be replaced with the end cap?
Yes. The listed assembly includes replacement seals. Replacing the seals at the same time helps provide a proper hydraulic seal and reduces the risk of reusing worn sealing components.
How do I confirm compatibility?
Compare the original end cap and listed reference numbers, then verify the engine brand, model, horsepower, stroke, year and serial number. Do not rely on horsepower alone because different engines can use different tilt-cylinder designs.
Shipping speed and cost
Typical transit is 5–15 days. Standard shipping is free where offered; expedited options, availability and delivery estimates are shown at checkout.
Warranty and returns
Warranty coverage and return eligibility are subject to the applicable store policy. Contact support with your order details before returning a product or beginning a warranty claim.
Safety & Important Information
- Support the outboard securely before working on the hydraulic tilt system.
- Relieve hydraulic pressure and use the correct service procedures and tools.
- Verify the original part, engine model, year and serial number before purchase.
- This is an aftermarket replacement, not an OEM Mercury component.
- Professional installation is recommended when the correct service procedure or torque specification is unavailable.
About Sea Sierra
- Pro-Grade Standards — Marine replacement parts selected for demanding real-world conditions.
- Fast Global Fulfillment — Standard delivery is available to most regions, with estimated timing shown at checkout.
- Manufacturer-Direct Value — Practical replacement solutions with attention to materials and quality control.
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