OMC Parts Drawing *Cobra *Mercruiser *Alpha SEI Outdrives
- Mercruiser Alpha One lower unit parts drawing
Lower gearcase housing exploded view component drawing 1 - 25
Last updated on 9/26/2023
- 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
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
$55.99
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
$288.95
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
$1499.96
12410 Housing
Item 1
P/N 12410 Upper water pump housing (1966 – 1990)
#46-96148T1
$29.00
$36.00
12810 Pump cup
Item 2
P/N 12810 Pump cup (included in upper housing and in P/N 12110 and 12120)
#48752
$5.00
$6.00
89840 Impeller
Item 3
P/N 89840 Impeller (1966 – 1990)
#47-89984T4
$15.00
$19.00
21720
Item 4
P/N 21720 Washers (3 units)
12-36001
$4.00
$4.00
12821 Screw OEM 10-30720
Item 5
P/N 12821 Screw
12-36001
$4.00
$4.00
21180
Item 6
P/N 21180 Lock nuts (5 units)
11-35888
$7.00
$8.00
12830 Seal
Item 7
P/N 12830 Seal
26-38970
$4.00
$4.00
12820 Tube guide
Item 8
P/N 12820 Tube guide
23-29804T
$4.00
$4.00
81160 O-ring
Item 9
P/N 81160 O-rings (5 units)
25-30613
$4.00
$4.00
21190 Lock nuts
Item 10
P/N 21190 Nut (5 units)
11-826709111
$9.00
$11.00
21490 Washers
Item 11
P/N 21490 Washer (5 units)
12-29245
$6.00
$7.00
11070 Key
Item 12
P/N 11070 Key
28-56654
$4.00
$4.00
31020 Gasket
Item 13
P/N 31020 Gasket
27-858524
$4.00
$4.00
12510 Wear plate
Item 14
P/N 12510 Wear plate
32435-1
$4.00
$4.00
31010
Item 15
P/N 31010 Gasket
27-85608-1
$4.00
$4.00
12310 Base
Item 16
P/N 12310 Water pump base (1970 – 1983 only)
46-57234A1
$25.00
$31.00
85040 Oil seal
Item 17
P/N 85040 Oil seal
26-16977
$8.00
$11.00
85070 Oil seal
Item 18
P/N 85070 Oil seal
26-89238
$9.00
$12.00
82260 O ring 25-33145
Item 19
P/N 82260 O-ring (5 units)
25-33145
$7.00
$9.00
31040
Item 20
P/N 31040 Gasket
27-856704
$4.00
$4.00
21570 Roller bearing
Item 21A
P/N 21570 Bearing (1970 – 1983 only)
31-53079A1
$23.00
$28.00
21580
Item 21B
P/N 21580 Bearing (1984 – 1997 only)
31-36387A1
$32.00
$40.00
23300 Shims
Item 22
P/N 23300 Shim
15-57007A1
$6.00
$7.00
21800
Item 23
P/N 21800 Washers (5 units)
12-29395
$5.00
$6.00
30010
Item 24
P/N 30010 Washers (5 units)
12-31266
$4.00
$4.00
85581 Oil seal
Item 25
P/N 85581 Oil seal
26-816464-1
$7.00
$9.00