Quicksilver 864363A1 Shift Plate Kit for MerCruiser Alpha One Stern Drive Carbureted Engines

The Quicksilver 864363A1 Shift Plate Kit is a genuine OEM Mercury Marine replacement assembly designed for MerCruiser Alpha One stern drives equipped with carbureted engines. This kit provides a modern, reliable upgrade to the older roller-lever style shift interrupt switch that has been discontinued, restoring proper shifting function and protecting your drivetrain.

The shift interrupt switch plays a critical role in your stern drive system — it momentarily interrupts the ignition signal during gear engagement, dropping engine torque just long enough for the clutch dog to disengage smoothly. Without a properly functioning shift plate assembly, engines may stall when shifting into gear or experience hard, binding shifts. This kit addresses those symptoms with a complete, ready-to-install assembly per MerCruiser Service Bulletin #2002-01.

Key Features:

• Genuine Quicksilver OEM shift plate kit — not an aftermarket substitute
• Upgrades discontinued older-design shift interrupt switch to current specification
• Direct bolt-on replacement for Alpha One Gen I and Gen II stern drives
• Resolves engine stall and hard-shift conditions on carbureted MerCruiser applications
• Issued per MerCruiser Service Bulletin #2002-01
• Backed by Mercury Marine's 1-year factory warranty against defects in materials and workmanship

Replaces Superseded Part Numbers: 39670A1, 39670A3, 39670A5, 39670A15, 39670A22, 39670A28, 39670A33, 8719752A6

This kit is for use with MerCruiser carbureted engines on Alpha One stern drives. Also sold under Mercury Marine part number 864363A-1.