Don’t miss another weekend. This genuine Mercury Marine THERMOSTAT ships fast and installs easily – get back on the water where you belong.

Built with Mercury Marine’s precision engineering, this thermostat ensures reliable operation across all engine RPM ranges. Part number 99080M is manufactured to exact Mercury Marine factory specifications for precision installation and optimal performance. Constructed from premium marine-grade materials designed to withstand harsh saltwater and freshwater environments.

Factory parts exist for a reason — they work. Part 99080M undergoes rigorous Mercury Marine quality testing that aftermarket manufacturers skip. The result? Reliable performance season after season.

Compatible Mercury Marine Engines

FITS: 30HP MARINER

• Fits MARINER 30HP engines
• Compatible HP: 30HP
• Covers 4 serial number ranges
• Configurations: Outboard
• OEM genuine Mercury Marine part

COMPLETE SERIAL NUMBER COMPATIBILITY:

30HP Models

• 30HP OUTBOARD (Mariner)

Not sure where to find your engine’s serial number? View our quick reference guide to locate it on your Mercury Marine engine.

Verification & Support

Want to verify compatibility for part 99080M? Use our parts finder tool for instant confirmation. Still have questions? No problem – use the contact buttons at the bottom of this page to reach us by text, call, or email

Trusted marine parts specialist since 1985. Low prices, fast shipping – most orders placed by 1pm ship today.