Tilt End Cap & Seals – Fits Mercury 75-250HP Outboard (Replaces 878239A02, 811606, 878239A1)
This replacement tilt cylinder end cap with seals is designed for a wide range of Mercury Marine V6 outboard engines from 1991 to 2017, rated from 75 to 250HP. It covers 2-stroke and 4-stroke models, including Optimax, EFI, and carbureted versions.
This assembly is a direct replacement for multiple OEM and aftermarket part numbers, ensuring broad compatibility for servicing your hydraulic trim/tilt system.
- Includes one tilt cylinder end cap with pre-installed seals for a complete repair.
- Constructed from Aircraft-Grade Aluminum with a Military Grade Type 3 Hard Coat Anodized finish for superior corrosion resistance and durability.
- Equipped with high-performance Viton and High-Grade Urethane seals designed to withstand the harsh marine environment.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Mercury |
878239A02 |
| Mercury |
878239A1 |
| Mercury |
811606 |
| Mercury |
8M0090322 |
| SAIL MARINE |
878239A02 |
| Five Star Marine |
FSM042 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
| 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 |
Technical Specifications
| Specification |
Value |
| 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 |
Package Contents
1 x Tilt End Cap with Seals (Replaces 878239A02, 878239A1, 811606, 8M0090322)
Installation Guide
- Safely secure the outboard motor in the fully tilted position using a motor support bracket.
- Thoroughly clean the area around the tilt cylinder end cap to prevent dirt and debris from entering the hydraulic system.
- Using a compatible spanner wrench, carefully loosen and remove the old tilt end cap. Be prepared for some hydraulic fluid to escape.
- Inspect the tilt ram rod and the inside of the cylinder for any scoring, pitting, or damage. Address any issues before proceeding.
- Lightly lubricate the new seals on the replacement end cap with fresh hydraulic fluid.
- Carefully thread the new end cap onto the cylinder by hand, ensuring it does not cross-thread.
- Tighten the end cap to the manufacturer's specified torque. Do not overtighten.
- Top off the hydraulic fluid reservoir and follow the manufacturer's procedure to bleed any air from the system.
Troubleshooting & FAQ
Q: How do I know if this end cap fits my Mercury outboard?
A: This cap is designed for most Mercury V6 2-stroke and 4-stroke engines from 75-250HP (1991-2017). To confirm fitment, please check the 'Compatible Engine Models' table on this page and cross-reference your engine's original part number (e.g., 878239A02, 878239A1). Note: This part does not fit L6 Verado models.
Q: What are the signs that my tilt end cap is failing?
A: The most common signs of a failing end cap are hydraulic fluid leaking around the tilt ram where it exits the cylinder, a "spongy" or weak tilt response, or the outboard motor slowly drifting down from its tilted position.
Q: What makes this different from the original Mercury part?
A: This is an aftermarket part engineered to meet or exceed OEM specifications. It features an upgraded housing made of aircraft-grade aluminum with a Military Grade Type 3 hard anodized finish for enhanced corrosion resistance, along with high-quality Viton/Urethane seals comparable to the original.
Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
-
Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
-
Fast Global Shipping: Free delivery worldwide in 5–15 days.
-
Direct from Manufacturer: Competitive pricing without compromising quality.