Bonbo Trim Cylinder End Caps with Seals — 2-Pack for 115–250HP Honda/Suzuki/Yamaha Outboards, Aluminum & O-Ring

Bonbo 2-pack screw end caps with seals restore and seal Showa-style trim cylinders on 115–250HP Honda, Suzuki and Yamaha 2- and 4-stroke outboards.

If your outboard’s power trim or tilt is leaking or losing pressure, the problem often comes down to worn end caps and O-rings on the trim cylinder. These replacement end screws are machined aluminum with rubber seals designed to match the fit and function of common OEM part numbers used across many Honda, Suzuki and Yamaha models. You get two complete end caps with seals so you can replace both sides or keep a spare aboard for quick repairs.

Which motors and models will these end caps fit?

These caps are intended for Showa-style trim cylinders used on 115–250 horsepower Honda, Suzuki and Yamaha 2- and 4-stroke outboards. They are produced to replace a range of OEM part numbers so you can cross-check compatibility before ordering.

• Compatible with 115–250HP outboards using Showa trim cylinders.
• Cross-references include 64E-43821-01-00 series and 48630-96J00 series OEM numbers.
• Check the supplied product images and dimensions against your existing cap before installation.

How does installing these caps improve trim cylinder performance?

Replacing damaged or corroded end screws and seals restores the hydraulic integrity of the trim cylinder, stopping leaks and helping the system hold pressure. Proper sealing reduces air ingress and fluid loss, which leads to smoother trim and longer component life.

• New O-rings prevent hydraulic fluid leakage and contamination.
• Durable aluminum alloy resists corrosion in a marine environment.
• Correctly fitted parts help maintain factory hydraulic pressure for consistent trim response.

Is installation difficult, and what tools are required?

Installation is straightforward for anyone comfortable working on outboard trim cylinders. You’ll need the correct cap removal/installation tool and basic hand tools; the package includes two end caps and seals so you can complete both sides without additional parts.

• Recommended: proper cap removal tool to avoid thread damage.
• Typical install: drain/secure cylinder, remove old cap, replace seals, thread new cap and torque to spec.
• Two caps included — ideal for twin repairs or one repair plus spare on board.

What are the materials and longevity characteristics?

These trim cylinder end screws are made from a high-strength aluminum alloy paired with rubber seals and O-rings chosen for marine durability. The combination offers resistance to corrosion, impact and wear so the replacement holds up under normal boating conditions.

• Aluminum alloy body for rust resistance and structural strength.
• Rubber O-rings and seals formulated for hydraulic fluid compatibility.
• Precision machining and hardness for long-term reliable sealing and thread integrity.

Who is this for: boat owners, mechanics and marine service pros who operate or service 115–250HP Honda, Suzuki or Yamaha outboards that use Showa trim cylinders. These replacement caps are aimed at anyone needing a durable, OEM-replacement-quality fix for leaking or damaged trim/tilt end caps—whether you’re doing preventive maintenance, repairing a leak, or carrying a spare for coastal trips. Always verify fit with your existing part numbers and the pictures before installation.