Give your Yamaha outboard the factory-tight prop stack it was born with by dropping in Spacer 2 (688-45997-01-00). Sitting between the rear thrust washer and gear-case shoulder on 75 hp–250 hp two- and four-stroke models, this precision ring keeps the prop hub centered and the load spread evenly across the shaft—even when you hammer down in a following sea.

**What makes the genuine spacer worth the swap **

• Marine-grade stainless alloy shrugs off salt, sand, and electrolysis far better than generic aluminum shims.

• Machined 35 mm ID / 48 mm OD (±0.02 mm) mates perfectly with Yamaha’s splined shaft—no filing, no wobble.

• 5 mm thrust face distributes torque so seals stay round and gear oil stays inside the case.

• Drop-in replacement for dozens of F90, F150, and V-6 offshore lower units; installs during any prop change.

Practical payoff? Smoother hole shots, quieter idle, and longer life for that pricey stainless wheel you just bolted on. Toss a spare spacer in your boat bag—because a six-ounce ring is a lot cheaper than a new output shaft if a worn shim lets the prop walk. One simple part, solid peace of mind every time you push away from the dock.

• Supersessions
  688-45997-00-00