Yamaha Trim Cylinder End Cap – Replaces 6H1-43821-11 – Single Unit | JLM Marine

Tilt Trim End Cap with Seal – Fits Yamaha 2-Stroke 55-90 HP (6H1-43821)

This aftermarket Trim Cap Assembly (6H1-43821-11) is designed for Yamaha 6H1 series outboard motors from 55 HP to 90 HP. Engineered to replace OEM part number 6H1-43821, this complete assembly features an upgraded process with an integrated oil seal for enhanced airtightness and durability on the power trim and tilt system.

This small cap assembly directly replaces Yamaha 6H1-43821-11-00 and fits a wide range of Yamaha outboard models from 1991 through 2009. It is compatible with Yamaha 55, 60, 70, 75, 80, 85, and 90 HP 2-stroke engines equipped with power trim and tilt assemblies.

• Single-Cap Assembly: Includes one trim cylinder end cap, one seal, and one O-ring. Sold individually, not as a pair.
• Enhanced Sealing: Features upgraded internal oil seal for superior airtightness compared to standard caps.
• Wide Compatibility: Fits multiple Yamaha 6H1 series trim and tilt assemblies across various horsepower ratings.

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 Yamaha owners, here's a guide to help you identify your engine's serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

Technical Specifications

Package Contents

This listing is for one trim cylinder end cap assembly, with the following components:

• TRIM CYLINDER END CAP (SCREW) 6H1-43821-11 × 1
• SEAL 6H1-43822-10 × 1
• O-RING 6H1-43861-10 × 1

Sold individually. This package does not include two end cap assemblies.

Installation Guide

1. Securely support the outboard, disconnect the battery, and relieve hydraulic pressure according to the service manual before beginning work.
2. Remove the old threaded trim cylinder end cap using the appropriate tool. Note the position and orientation of the seal and O-ring.
3. Clean the mounting surface thoroughly, removing dirt, corrosion, and any residue as directed by the service manual.
4. Install the O-ring (6H1-43861-10) in its specified location according to the service manual. Ensure it seats properly without twisting.
5. Install the seal (6H1-43822-10) in the cap assembly in the orientation specified by the service manual.
6. Align the new end cap (6H1-43821-11) with the cylinder threads and carefully start threading it by hand to avoid cross-threading.
7. Tighten the threaded end cap with the appropriate tool to the torque specified in the service manual for your trim unit.
8. Follow the service manual's fluid filling and bleeding procedures, reconnect the battery, and test trim/tilt operation while checking for hydraulic leaks.
9. Inspect the cap area after initial operation. If leakage or abnormal operation occurs, stop using the system and inspect it before further use.

Troubleshooting & FAQ

How do I confirm this trim cap fits my Yamaha outboard?
Verify your engine model and year in the compatibility table above. Cross-reference your trim/tilt assembly part numbers with the listed OEM numbers, particularly 6H1-43821 or 6H1-43821-11-00. If your model is listed, this cap assembly will fit.

What are the signs that my trim cylinder end cap needs replacement?
Common symptoms include hydraulic fluid leaking from the trim cylinder end, loss of trim/tilt pressure, slow trim response, or visible damage to the cap or seals. If you notice oil around the small cap assembly, replacement is recommended.

How often should I replace the trim cap seals?
Replace seals whenever you notice leakage or loss of hydraulic pressure. Proactive replacement is recommended every 3–5 years or during major trim/tilt service, especially in saltwater environments where corrosion accelerates seal degradation.

What is included in this listing?
This listing includes one trim cylinder end cap (6H1-43821-11), one seal (6H1-43822-10), and one O-ring (6H1-43861-10). The term “screw” refers to the threaded end cap itself, not a separate mounting screw.

Is this a single end cap or a pair?
This listing is for one end cap assembly, not a pair. If you need to replace two matching end caps, order a quantity of two.

What is the difference between this aftermarket cap and the OEM version?
This aftermarket replacement is built to OEM specifications with an upgraded process that includes an internal oil seal for enhanced airtightness. It offers equivalent or improved sealing performance compared to the original Yamaha part.

OEM vs. Aftermarket?
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.

How fast do you ship and how much does it cost?
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.

What is your warranty and return policy?
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.