MasterGuard Installation Kit 12 – Hub Kit for 25–75hp Outboards (3.5" Gearcase)

MasterGuard Installation Kit 12 — 3.5" Gearcase, 25–75hp Outboards

The MasterGuard Installation Kit is the hub system that connects your propeller to your outboard’s driveshaft. Kit 12 is designed for 25–75hp outboards with a 3.5-inch gearcase, and is compatible with Hustler and Express Mach3 propeller housings. It’s the only hub kit in the industry backed by a Lifetime Warranty — including coverage even if the propeller is destroyed in a strike.

Best Use Case

Kit 12 is the correct hub kit for boaters running Hustler or Express Mach3 propellers on 25–75hp outboards with a 3.5-inch gearcase. It’s also the smart choice for anyone replacing an older rubber-sleeve or multi-part hub system — the one-piece MasterGuard design eliminates the most common failure points found in conventional hub kits, and can be reused after most prop strikes rather than replaced. Always confirm your engine make, model, and year against the application chart before ordering.

Key Features

• Lifetime Warranty — The only hub kit in the world with a lifetime warranty, with no restrictions for normal consumer use. Covered even if the propeller is destroyed in a strike.
• One-Piece Bronze & Glass-Filled Nylon Construction — Durable marine bronze splines over-molded with glass-reinforced polymer. Eliminates the cracking, spinning, and failure points common in multi-part sleeve-and-spline designs and pressed-in rubber hub systems.
• Reusable After Prop Strikes — Designed to absorb impact and protect your lower unit. In most cases the hub can be reinstalled after a strike, saving the cost of a full propeller replacement.
• Saves Up to 33% on Replacement Propellers — Because the hub stays with the engine, you only need to replace the propeller housing after a strike — not the entire assembly.
• Shock & Vibration Absorption — The high-tech polymer cushion absorbs shift shock and harmful vibrations, reducing stress on the engine and drivetrain.
• Small-Diameter Design — Allows for greater exhaust flow and more efficient power delivery at the prop.
• OEM-Compatible — Adapts to the factory thrust washer and prop nut. No special tools required.
• Compatible Engine Brands — Fits Colman, Evinrude, Honda, Johnson, Mariner, Mercury, Nissan, Parsun, Suzuki, Tohatsu, and Yamaha outboards.

Specifications

• Part Number: 11300200
• Kit Number: 12
• Series: 10-Series
• Gearcase: 3.5"
• Compatible Engine Range: 25–75hp outboards
• Compatible Propeller Lines: Hustler, Express Mach3 (3.5" gearcase housings)
• Includes: Hub assembly, prop nut spacer, installation instructions

Parts Desk Insights

Always verify your kit number using the application chart. Hub kit numbers are engine-specific — the correct kit depends on your engine make, model, year, and gearcase size. Kit 12 covers a range of 25–75hp applications with a 3.5-inch gearcase, but other kit numbers in the 10-Series may be required for your specific engine. Check the adjacent kits if yours isn’t listed:

• MasterGuard Kit 11 — 10-Series, 3.5" Gearcase
• MasterGuard Kit 13 — 10-Series, 3.5" Gearcase

Looking for a hub kit for a different gearcase or horsepower range? Browse the full MasterGuard lineup:

• MasterGuard Kit 21 — 20-Series (3" Gearcase, 9.9–35hp)
• MasterGuard Kit 22 — 20-Series (3" Gearcase, 9.9–35hp)
• MasterGuard Kit 500 — 500-Series (4.75" Gearcase, 90–200hp)
• MasterGuard Kit 501 — 500-Series (4.75" Gearcase, 90–200hp)
• MasterGuard 700-Series Hub Kit (200hp+)

Need a compatible propeller for this gearcase? See the full propeller collection and filter by 3.5" gearcase.