Engine acting up? Don’t let a faulty part keep you off the water. This genuine Mercury Marine THUMB SCREW ASSEMBLY restores reliable performance and gets you back to what you love.

Factory-built to exact Mercury Marine specifications, this component ensures reliable operation across all engine RPM ranges. Part number 22477A4 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.

Smart boat owners know: buying cheap parts twice costs more than buying genuine Mercury once. Part 22477A4 delivers long-term value through superior materials and precision manufacturing.

Compatible Mercury Marine Engines

FITS: 60-200HP MARK, MERCURY

• Fits MARK, MERCURY 60-200HP engines
• Compatible HP: 60HP, 100HP, 200HP
• Covers 14 serial number ranges
• Configurations: Outboard
• OEM genuine Mercury Marine part

COMPLETE SERIAL NUMBER COMPATIBILITY:

60HP Models

• 60HP OUTBOARD (Mercury): 2385673-2387383

100HP Models

• 100HP OUTBOARD (Mercury): 1290910-1499331

200HP Models

• 200HP OUTBOARD (Mercury): 1558310-1866495, 1866496-2296266, 2296267-2827676, 2827677-3226957, 3226958-3537530, 3537531-4709592, 7012358-7098522, 8006265-8045198, 9016254-9157229

HP Models

• HP OUTBOARD (Mark)

Need help finding your serial number? Check our serial number location guide for step-by-step instructions on locating it on your Mercury engine.

Verification & Support

Verify part 22477A4 works with your Mercury using our parts finder tool. Have questions? Reach out using the contact buttons at the bottom of this page — our team is here to help by text, call, or email

Trusted marine parts specialist since 1985. Best prices guaranteed – free shipping on orders over $100.