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OMC Evinrude Johnson outboard identification

Lower unit gearcase drawings and diagram

Last updated on 12/10/2023

  • Johnson outboard and Evinrude lower unit models
  • Smaller old style 3-1/2 inch hub years 1975-1988
  • New style years 1989-2005
  • Large gearcase years 1975-2006
  • V4 90 degree years 1978-1998
  • V4 60 degree years 1995-2006
  • 4-5/8 inch hub type O unit. 4 and V6 years 1979-2006
  • 5-1/16 hub type M V4 and V6 years 2002 to 2006

Small gearcase old style years 1975-1988

15-1/2 inch tall.
Cavitation plate to propeller shaft 6-7/8 inch.
Hub area is 3-1/2 inch.
Straight at the trailing end of the gear housing and the fin.
Pointed at the trailing end of the cavitation plate.
Four hole internal water intake screen.
No speedo pitot.

Lower unit gearcase

Old style 1975-1988

Small gearcase New style years 1989-2005

15-3/4 inch tall.
Cavitation plate to propeller shaft 6-7/8 inch.
Straight at the trailing end of the gear housing and the fin.
Pointed at the trailing end of the cavitation plate.
Six holes above the cavitation plate.
External water intake screen.
Hub area is 3-7/8 inch.
Includes speedo pitot.

Lower unit gearcase

1989-2005

Large gearcase assembly years 1975-2006

Physical Characteristics are: 17-7/16 inch tall.
Cavitation plate to propeller shaft 7-1/8 inch.
Hub area is 4-1/16 inch.
Straight at the trailing end of the gear housing and the fin.
Pointed at the trailing end of the cavitation plate.
Six holes above the cavitation plate.
Internal water intake screen has three holes.
No speedo pitot.

Large gearcase-1975-2006

V4 90 degree small gearcase assembly years 1978-1998

Physical Characteristics are: 19-3/16 inch tall.
Cavitation plate to propeller shaft 7-1/4 inch.
Hub area is 4-1/8 inch.
Straight at the trailing end of the gear housing and the fin.
Pointed at the trailing end of the cavitation plate.
Six holes above the cavitation plate.
Internal water intake screen has four holes.
No pitot.

rear view

Small Gear case Type V4 60 degree years 1995 to 2006

Physical Characteristics are:
19-1/16 inch tall.
Curved at the trailing end of the gear housing and fin.
Flat at the trailing end of the cavitation plate.
cavitation plate to propeller center 8 inch.
2 slots above the cavitation plate.
External water intake screens.

side view

Lower unit gearcase

Small Gear case Type V4 60 degree years 1995 to 2006

Physical Characteristics are:
19-1/16 inch tall.
Curved at the trailing end of the gear housing and fin.
Flat at the trailing end of the cavitation plate.
cavitation plate to propeller center 8 inch.
2 slots above the cavitation plate.
External water intake screens.

Lower unit gearcase

Side and top view

Large gearcase type M V4 / V6 years 2002-2006

19-3/16 inch tall.
Cavitation plate to propeller shaft 8-1/4 inch.
Hub area 5-1/16 inch.
Curved at the trailing end of the gear housing and the fin.
Flat at the trailing end of the cavitation plate.
Three slots above the cavitation plate.
External water intake screens.
Includes speedo pitot.

Lower unit gearcase

Type M 2002-2006