Hihitomorrow Trim Cylinder Cap Kit for Suzuki & Yamaha 115-300 HP — 2-Piece Aluminum Caps with Seals & O-ring

Hihitomorrow 2-piece trim cylinder cap kit includes two aluminum alloy caps, seals and O-ring to replace worn caps on select Suzuki and Yamaha outboard trim cylinders.

This replacement kit provides the external caps and internal sealing components needed to restore hydraulic trim cylinder ends on a wide range of Suzuki and Yamaha outboards (115–300 HP models specified by fitment). Designed as a direct-fit aftermarket alternative to multiple OEM part numbers, the set helps stop leaks, re-establish proper sealing and keeps trim cylinders protected from corrosion and wear when installed correctly.

Which motors and years will this trim cap kit fit?

This kit lists compatibility with many Suzuki and Yamaha 2- and 4-stroke outboards across model years — check bore and HP details to confirm fit. It covers Suzuki 4-cylinder and 6-cylinder 4-stroke models in the 115–300 HP ranges and Yamaha 4- and 6-cylinder 4-stroke and HPDI models as noted.

• Suzuki coverage: select 115–200 HP 4-cylinder years and 200–300 HP 6-cylinder years (refer to provided HP and year ranges).
• Yamaha coverage: applicable 115–300 HP 4- and 6-cylinder models with specified bore sizes and SHO/HPDI variants.
• Compare your engine’s part number or cylinder bore to the kit’s OEM replacements before ordering.

How does this kit restore a leaking or worn trim cylinder?

By replacing the end caps and O-ring seals, the kit renews the mechanical barrier that keeps hydraulic fluid contained and shields the cylinder interior from water and corrosion. New seals and a corrosion-treated alloy cap help re-establish pressure integrity and reduce external water ingress when installed with proper torque and clean mating surfaces.

• Includes new rubber seals and an O-ring sized to OEM specifications for tight sealing.
• Aluminum alloy caps are corrosion-resistant to extend component life in marine environments.
• Restores fitment to OEM part number equivalents for accurate sealing and alignment.

What are the construction and quality features of this replacement set?

The trim cap kit combines treated aluminum alloy for the caps with molded rubber seals designed for hydraulic service. The materials are selected to resist rust and corrosion from saltwater exposure while maintaining the flexibility needed for hydraulic sealing.

• Aluminum alloy cap body with anti-corrosion surface treatment.
• Durable rubber seals engineered to resist hydraulic fluid and marine conditions.
• Packaged as a two-piece set with seals and an O-ring for both cylinder ends.

How should I install and verify correct fitment?

Installation requires removing the old caps, cleaning mating faces, seating new seals and torquing the caps to the manufacturer’s specification. Always confirm engine model, cylinder bore, and OEM part cross-references before fitting; if unsure, consult a marine technician.

• Clean the cylinder end and mating surfaces thoroughly before assembly.
• Lubricate the O-ring with compatible hydraulic fluid to seat smoothly without twisting.
• Use proper torque values and inspect for leaks during initial operation.

Who is this for: This Hihitomorrow trim cylinder cap and seal kit is aimed at boat owners, marine mechanics and service shops repairing Suzuki and Yamaha outboards that match the listed HP and bore specifications. If you need an OEM-equivalent cap assembly to stop leaks, replace corroded end caps or maintain hydraulic trim integrity on compatible 115–300 HP engines, this kit offers a practical aftermarket option. Confirm your engine’s year, cylinder bore and OEM part numbers before purchase to ensure a correct match.