OMC Parts Drawing *Cobra *Mercruiser *Alpha SEI Outdrives

Lower gearcase housing exploded view component drawing 1 - 25

Last updated on 11/15/2023

  • Mercruiser and Alpha One (up to 1990) exploded view lower unit drawing
  • Water pump components, impellers, seals and shafts
  • Manufactured by GLM, California. All parts include a 2 year warranty
  • Easy to identify photos with OEM Mercury numbers
Mercruiser outdrive parts drawing 51-77, Mercruiser Alpha One lower unit parts, Mercruiser outdrive components #26-50

Photo

Description / OEM #

Price
(USD)

Price (Canadian)

12110 Water pump

Item A
P/N 12120
 Complete water pump kit (1984 – 1990, MR and Alpha One, serial numbers 6854393-OD469858). Click on picture for older MC-1, R and 1991 and up Gen 2 models.

$42.99

$ 63.89

51220 GM manifold

Item B
P/N 51220
 GM 4.3L V6 exhaust manifold, center rise for 1986 and up models. Click on photo for all other engine / model manifolds.

99746A17

$218.95

$ 375.89

SEI Marine Mercruiser

Lower Unit 1623-8951A43

Item C
SE106
Aftermarket SEI lower unit Mercruiser / Alpha One Gen 1 complete lower units. For 1970 – 1990 models, serial numbers 2791957-OD469858 with 13 spline vertical driveshaft, for up to 300 horsepower.

OEM 1623-8951A43

$1125.96

$1499.89

Mercruiser Alpha One lower unit parts

12410 Housing

Item 1
P/N 12410
 Upper water pump housing (1966 – 1990)

#46-96148T1

$29.00

$ 54.89

Mercruiser Alpha One lower unit parts

12810 Pump cup

Item 2
P/N 12810
 Pump cup (included in upper housing and in P/N 12110 and 12120)

#48752

$5.00

$ 8.89

89840 Impeller

Item 3
P/N 89840
 Impeller (1966 – 1990)

#47-89984T4

$15.00

$ 24.89

21720

Item 4
P/N 21720
 Washers (3 units)

12-36001

$4.00

$4.89

12821 Screw OEM 10-30720

Item 5
P/N 12821
 Screw

12-36001

$4.00

$ $ 6.89

21180

Item 6
P/N 21180
 Lock nuts (5 units)

11-35888

$7.00

$4.89

12830 Seal

Item 7
P/N 12830
 Seal

26-38970

$4.00

$4.89

12820 Tube guide

Item 8
P/N 12820
 Tube guide

23-29804T

$4.00

$ $ 6.89

81160 O-ring

Item 9
P/N 81160
 O-rings (5 units)

25-30613

$4.00

$4.89

21190 Lock nuts

Item 10
P/N 21190
 Nut (5 units)

11-826709111

$9.00

$4.89

21490 Washers

Item 11
P/N 21490
 Washer (5 units)

12-29245

$6.00

$4.89

11070 water pump impeller key.

11070 Key

Item 12
P/N 11070
 Key

28-56654

$4.00

$4.89

31020 Gasket

Item 13
P/N 31020
 Gasket

27-858524

$4.00

$4.89

Mercruiser Alpha One lower unit parts

12510 Wear plate

Item 14
P/N 12510
 Wear plate

32435-1

$4.00

$ 6.89

31010

Item 15
P/N 31010
 Gasket

27-85608-1

$4.00