Slide this Mercury Sleeve–Prop Bore (23-8M0214998) over the prop‐shaft splines and give your outboard the snug, vibration-free fit it deserves. Molded from Mercury’s impact-modified polymer, the sleeve fills the minute gap between hub and bore on Alpha, Bravo, and late-model FourStroke drives—so every ounce of thrust pushes the boat, not the shaft.

What this little sleeve really does

• Centers the prop dead-true, cutting rattle and cavitation at idle and wide-open throttle alike.

• Absorbs shock loads with a self-lubricating shell that won’t crack under hard reverse or sudden throttle punches.

• Protects splines and seals by keeping exhaust gases out of the hub cavity and corrosive water away from the shaft.

• Drops in by hand during any prop change—no tools, no sealant, no guessing on fit.

The result? Smoother hole-shots, cleaner shifting, and longer life for that pricey stainless wheel. Keep a spare in the tackle box; the five-minute swap pays for itself every time you feel the prop lock on with that confident, factory-tight click. Small part, big difference in how your Mercury runs and feels.