48-78116A40 48-78116A45 Mercury Black Max 15 1/4 x 15 Aluminium Propeller – RH 15 Spline | Genuine Used Part

🔧 Product Description

Genuine Mercury Black Max 15 1/4 x 15 Aluminium Propeller - Part Number: 48-78116A40 / 48-78116A45

A genuine used Mercury Black Max three-blade right-hand aluminium propeller for Mercury, Mariner and compatible sterndrive 4 3/4-inch large gearcases.

The large 15 1/4-inch diameter and 15-inch pitch provide strong thrust and load carrying for heavier boats. Depending on application, Mercury Flo-Torq II or Flo-Torq IV hub hardware is used with the later A45 propeller.

⚙️ Key Features

• Genuine Mercury / Quicksilver Black Max propeller
• 15 1/4-inch diameter x 15-inch pitch
• Three-blade aluminium construction
• Right-hand rotation with 15-tooth large-gearcase application
• Suitable for large outboards and compatible Alpha / Bravo sterndrives

🚤 Compatibility

Commonly used on

• Mercury and Mariner 4 3/4-inch large outboard gearcases
• MerCruiser Alpha One and Bravo One single-prop sterndrives

Typically suits

• Engine models:
• Mercury / Mariner 135HP, 150HP, 175HP and 200HP V6 two-stroke, EFI and OptiMax outboards
• Mercury / Mariner 225HP, 250HP and 300HP large-gearcase outboards
• Mercury Verado and Pro XS models using the compatible 15-spline hub and propeller clearance
• MerCruiser Alpha One sterndrives using the 15-spline propeller shaft
• MerCruiser Bravo One sterndrives using the 15-spline propeller shaft
• OMC Cobra / King Cobra and Volvo Penta SX installations only where the compatible hub kit and thrust hardware are used
• HP Range: 135HP - 300HP outboards, plus compatible sterndrives
• Engine Type: Mercury / Mariner large-gearcase outboard or MerCruiser single-prop sterndrive
• Year Range: Approximately late-1970s onward, gearcase and hub-kit controlled

🔌 Function

The propeller converts engine torque into forward thrust. The large diameter and 15-inch pitch are suited to heavier hulls requiring strong acceleration, grip and lower planing speed.

⚠️ Common Signs of Failure

• Blades are bent, chipped, cracked or out of track
• The hub slips and engine RPM rises without matching boat speed
• Propeller vibration increases with engine speed
• Cavitation, ventilation or poor acceleration develops after impact damage
• Hub splines, thrust faces or retaining surfaces are worn or corroded

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 48-78116A45 → Supersedes 48-78116A40
• 48-78116A40 → Replaces 48-78116A4
• 48-78116A4 → Replaces earlier 48-73504A4 and 48-75760A4

OEM / Related Numbers

• 48-78116A40
• 48-78116A45
• 48-78116A4
• 48-73504A4
• 48-75760A4
• 835257K1 related Flo-Torq II hub kit
• 835257K10 related Flo-Torq IV hub kit for designated high-torque applications

Aftermarket / Verified Equivalents

• Quicksilver Black Diamond: QA2008X - 15 1/4 x 15 aluminium equivalent
• Michigan Wheel: 992002 - 15 1/4 x 15 modular-hub replacement
• Engineered Marine Products: P9511-1525-15 - 15 1/4 x 15 aluminium equivalent
• Solas Amita 3 / Rubex 3: 15-pitch large-gearcase aluminium alternative with the correct hub

📦 Condition

• Genuine used part
• Removed from running engine where applicable
• In good working condition unless otherwise stated