Skip to main content

OMC Parts Drawing *Cobra *Mercruiser *Alpha SEI Outdrives

Johnson outboard lower unit

Type "O" Johnson / Evinrude 1979 to 2006 all new SEI gearcase replacement with no core required.

  • V4 gear ratio 2.25:1 teeth 12:27 without speedo 5004639
  • V6 gear ratio 1.83:1 teeth 12:22 without speedo 5005401

Johnson outboard lower unit aftermarket SEI replacement

Johnson outboard V4 lower unit
  • Shafts are available that clip into lower units for 20 and 25 inch.
  • You will have to take apart your old unit and remove the pin that’s holds the shaft in place.
  • See upper drive shaft page for new shafts.

Lower unit

28880 Complete aftermarket replacement gearcase

28880 Complete gearcase V4

P/N 28880 
Complete replacement gear case with out speedo for OMC V4 gear ratio 2.25:1 teeth 12:27 OEM 5004639 
 

100 hp. WPL 20 inch transom year 1999
100 hp. WPX 25 inch transom year 1999
100 hp. Commercial 20 – 25 inch transom 1988 – 1997
100 hp. WQ,X, and 105 hp. WEX 25″ transom 1998


105 hp. Commercial WPL 20″ transom 2000 – 2001
105 hp. Commercial WPX 25″ transom 2000 – 2001
105 hp. Com. WEL 20″ transom years 2000 – 2001
105 hp. WEL 20 inch transom year 1998
105 hp. WRL 20 inch transom years 1997 – 1998
105 hp. WRX 20 inch transom year 1997 – 1998
105 hp. RWL 20 inch transom year 1998
105 hp. RWY 20-1/5 inch transom year 1998
105 hp. RWX 25 inch transom year 1998


115 hp. FPX / FX 25 inch transom years 2000 – 2001
125 hp. RWL 20 inch transom years 1995 – 1997
125 hp. RWY 22-1/2 inch transom years 1995 – 1998
125 hp. WPTL 20 inch transom years 1992 – 1998
125 hp. WTPX 20 inch transom years 1988 – 1998


130 hp. 20 and 25 inch transom years 1995 – 1998
V4 60 degree Loop charged 25″ transom 1995 – 2006
140 hp. 25 inch transom years 1988 – 1994

$1195.00

$146.89

28810 V6

P/N 28810 GLM replacement lower unit with out speedo for OMC V6 gear ratio 1.83:1 teeth 12:22 OEM 5005401

135 hp. FSL / FS 20 inch transom 2000 – 2001

135 hp. FPX / FX 25 inch transom 2000 – 2001

V6 60 degree loop charged 20 inch transom with external screens years 1995 – 2000

V6 60 degree loop charged 25 inch transom with external screens years 1991 – 1999

150 hp. Commercial 20 and 25 inch transom year 1993 – 1999

155 hp. Commercial 20 and 25 inch transom year 1988 – 1992

$2599.00

$3571.89

28710 V6 with speedo

P/N 28710 
 
Complete gear case with speedo for OMC V6 gear ratio 1.83:1 teeth 12:22 with speedo OEM 5004635

135 hp. FPL/FL 20 inch transom years 2000 – 2001

V8 Crossflow 20 inch transom and 90 degree loop charged years 1988 – 1991

V6 Crossflow 25 inch transom and 90 degree loop charged years 1988 – 1991

V6 90 degree loop charged 20 inch transom years 1992 – 1999

$2299.00

$4317.89

Side and top view

Large Gearcase “0” Type V4 and V6 years 1979 to 2006

Physical Characteristics are:
19-3/16 inch tall.
Cavitation plate to prop shaft 8-1/4 inch.
Hub area 4-5/8 inch.
Straight at the end of the gear housing and the fin.
Pointed at the end of the cavitation plate.
Two slots above the cavitation plate.
External water intake screens.