Yamaha - Oil Tank Cap Assembly - Lubrication System Component - 6H4-21770-01-00

Overview

I’ve learned not to overlook something as simple as an oil tank cap, especially on older two-stroke setups. A worn or loose cap can let air into the system or allow contamination, and that’s where problems start. This updated version replaces the older one and gives you a better, more reliable seal. It’s a small upgrade that helps keep your oil system doing its job without issues.

Key Features

• Updated Replacement Design – Supersedes earlier version to maintain proper fit and improved reliability.
• Secure Oil System Seal – Helps keep the oil supply protected from air and outside contaminants.
• Proper Venting Support – Allows consistent oil flow by maintaining correct tank pressure.
• OEM Fitment Construction – Built to Yamaha specifications for dependable sealing and installation.
• Durable Marine Build – Designed to handle heat, vibration, and long-term exposure to marine conditions.

Engine & Boat Compatibility

Designed for Yamaha outboards equipped with compatible oil injection systems. Commonly used across small to mid-size two-stroke engines found on fishing boats, skiffs, and recreational vessels. Always verify compatibility with your specific engine before installation.

FAQ

Q: What’s the difference between this and the older version?
A: This part replaces the earlier version with updated design improvements for better fit and reliability.

Q: What happens if the oil tank cap doesn’t seal properly?
A: Air or contaminants can enter the system, which can affect oil delivery and engine protection.

Q: How tight should the cap be installed?
A: Snug and secure is enough—over-tightening isn’t necessary and can wear out the seal.

Q: Can this cause oil system alarms if it’s bad?
A: In some cases, yes—improper sealing can lead to inconsistent oil flow and trigger warnings.

Q: How often should I check or replace this cap?
A: It’s a good idea to inspect it during routine maintenance and replace it if you see wear or damage.