OMC Parts Drawing *Cobra *Mercruiser *Alpha SEI Outdrives
- Mercruiser lower gear case parts 26 to 50
Alpha One and Mercruiser outdrive components with drawing
Updated April 11th 2026
- Alpha One ( up to 1990 ) and Mercruiser lower unit GLM parts.
- Gears, gear sets and shifter components.
- OEM Mercury cross reference numbers.
Mercruiser outdrive components #26-50
Photo
Description / OEM #
Price
(USD)
Price (Canadian)
12120
Item B
12120
Water pump kit with housing (1984 – 1990, MR and Alpha One
serial numbers
6854393 – OD 469858). Click on picture for older MC-1, R and 1991 and up Gen 2 kits.
$35.95
$ 63.89
Lower Unit
1623 - 8951 A43
SE106 SEI Mercruiser sterndrive
Item C
SEI SE106
SEI after market lower gear case Mercruiser, MR / Alpha One Gen 1 complete lower unit.
Years 1970 to 1990 models.
Serial numbers 2791957 – OD 469858
4 cyl., V6 and V8 models for up to 300 horse power.
OEM 1623 – 8951 A43
$1229.99
$1799.99
51230
Item D
51230 GM 5.0 liter and 5.7 liter engines
305 – 350 V8
Center rise for years 1983 to 2001 models. Click on photo for all other engine models.
860246 Q11
$379.99
$531.99
21030 lower shift shaft
Item 30
P/N 21030 Shift shaft
77481 – 1
$37.95
$ 62.89
11100
43 – 96084A7
$623.95
$ 333.89
