878239A02 Tilt End Cap with Seals for Mercury Mariner | JLM Marine

Tilt End Cap with Seals for Mercury Mariner – 878239A02

This tilt end cap with seals is engineered for Mercury and Mariner outboard motors ranging from 75 HP to 250 HP, covering a wide range of DFI, EFI, Pro XS, and Sport XS models. Designed to integrate seamlessly with power trim components on both metal motor housing and three-ram power trim systems, it ensures reliable tilt operation and fluid containment.

This aftermarket replacement directly cross-references Mercury OEM part numbers 878239A02, 8M0090322, 878239, 811606, and 878239A1, as well as FSM042 and 878412A1, providing a cost-effective solution without compromising performance.

• Includes integrated seals for complete installation
• Compatible with both metal motor housing and Design II three-ram power trim systems
• Direct fit for Mercury and Mariner outboards from 1991 through current models

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

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.

Package Contents

1 × Tilt End Cap & Seals

(The package contains all the parts shown in the picture.)

Installation Guide

1. Disconnect the battery and relieve hydraulic pressure from the power trim system before beginning work.
2. Remove the old tilt end cap by loosening retaining bolts; note the orientation for reassembly.
3. Inspect the mounting surface for debris, corrosion, or damage; clean thoroughly with a non-abrasive cleaner.
4. Position the new seals into the grooves on the tilt end cap, ensuring they are seated evenly without twisting.
5. Apply a thin layer of marine-grade grease to the seals to aid installation and prevent pinching.
6. Align the new tilt end cap with the mounting holes on the power trim assembly.
7. Insert and hand-tighten retaining bolts in a crisscross pattern to ensure even seating.
8. Torque bolts to the manufacturer's specification (consult your service manual for exact values).
9. Reconnect hydraulic lines if detached, ensuring all fittings are snug and free from cross-threading.
10. Bleed the power trim system to remove any air introduced during installation.
11. Reconnect the battery and test tilt operation through full range of motion, checking for smooth movement and leaks.
12. Inspect all connections and seals after initial operation; retighten bolts if necessary.

Troubleshooting & FAQ

Q: How do I confirm this tilt end cap fits my engine?
A: Cross-reference your engine's serial number with the compatibility table above, or verify the original part number on your tilt end cap matches one of the OEM numbers listed (878239A02, 8M0090322, 878239, 811606, 878239A1). Use the Mercury Serial Number Guide linked above to locate your engine details.

Q: What are the common signs that my tilt end cap or seals need replacement?
A: Look for hydraulic fluid leaks around the power trim motor housing, sluggish or erratic tilt/trim operation, or visible cracks and wear on the end cap. If seals are hardened, flattened, or missing chunks, replacement is necessary to prevent further fluid loss and system damage.

Q: Can I reuse the old seals if they look okay?
A: We do not recommend reusing old seals. Even if they appear intact, they may have taken a compression set or lost elasticity, leading to premature leaks. Always install new seals when replacing the tilt end cap.

Q: Will this part fit both metal motor housing and three-ram Design II trim systems?
A: Yes, this tilt end cap is compatible with both metal motor housing power trim assemblies and three-ram Design II systems as specified in the compatibility table. Confirm your system type using your engine's serial range.

Q: How often should I replace the tilt end cap and seals?
A: Replacement intervals vary based on usage and operating environment. Inspect seals annually and replace immediately upon detecting leaks, cracks, or hardening. High-use or saltwater applications may require more frequent inspection.

Q: What is the difference between this aftermarket part and the OEM version?
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.