MerCruiser MR/Alpha One Gear Housing Diagram
Ref
Part #
Note
Qty
Description
-
1623-8951A43
1
Gear housing assembly - complete
1
1623-8951A37
1
Gear housing assembly
2
17-37972 1
1
Shift crank pin
3
16-46911
1
Stud (7/16-20 x 3-3/16”)
4
16-56298
2
Stud (7/16-20 x 1-31/32”)
5
16-56297 2
1
Stud (5/16-24 x 3-3/8”)
6
16-69501
2
Stud (1/4-28 x 3-1/4”)
7
26-45577 1
1,2
1
Seal
8
17-35973
2
Dowel pin
9
31-42647A 1
1
Roller bearing
10
NLA
1
Water pickup insert (starboard)
11
93424 1
1
Water pickup insert (port)
12
10-76156
1
Screw
13
11-45812
1
Nut
14
NLA
1
Dowel pin
15
45-42634
1
Driveshaft assembly
16
15-42637A1
AR
Shim kit
17
31-36387A1
1
Tapered roller bearing assembly
18
824519 1
1
Retainer
19
43-878087A4
1
Gear set (forward & pinion)
20
12-92721
1
Washer
21
11-35921
1
Nut (5/8-18)
22
10-67892A1
1
Screw
23
12-19183 3
1,2
1
Washer
24
46-44292A3
1
Water pump base assembly
25
27-42631 1
1,2
1
Gasket
26
25-90011
1,2
AR
O-ring
25-38099
1
AR
O-ring
27
26-89238
1
1
Oil seal
28
26-16977
1
1
Oil seal
29
27-85608 1
1,2
1
Lower gasket
30
27-858524
1,2
1
Upper gasket
31
32435 1
2
1
Face plate
32
46-96148T1
2
1
Water pump body assembly
33
48752T
2
1
Insert
34
26-38970
2
1
Water inlet tube seal
35
47-89984T4
2
1
Impeller
36
28-56654
2
1
Impeller key
37
10-96411
2
1
Screw
38
11-826711 9
2
Nut (1/4-28)
39
12-29245
2
Washer
40
11-13436
1
Nut (5/16-24)
41
12-36001
1
Washer
42
25-30271
2
1
Rubber ring
43
25-30613
1,2
1
O-ring (driveshaft)
44
25-29804T
2
1
Guide sleeve
45
77481 1
1
Lower shift shaft
46
53-29641
1
Retaining clip
47
12-27880
1
Washer
48
25-25439
1
1
O-ring
49
23-30617A2
1
1
Shift shaft bushing assembly
50
26-89236 1
1
Oil seal
51
12-31266
1
1
Rubber washer
52
12-29395
1
Shift shaft washer
53
76865
1
Shift crank
54
18-46950 1
1
Cotter pin
55
818349T1
1
Shift spool assembly
56
15-47397A1
AR
Shim kit
57
31-35928T1
1
Tapered roller bearing assembly
58
-
1
Forward gear (see #19)
59
31-42679
1
Roller bearing (Torrington # GB-1616)
31-30895T
1
Roller bearing (Torrington # B-1616)
60
52-853594T
1
Sliding clutch
61
17-30632
1
Cross pin
62
24-30893
1
Spring
63
44-824110
1
Propeller shaft
64
43-824109A1
1
Reverse gear
65
68100 1
1
Thrust ring
66
30-88957T
1
Ball bearing
67
25-31534
1
1
O-ring
68
73020A14
1
Bearing carrier (casting 73020C)
818763A10
1
Bearing carrier (casting 73020C1)
69
31-30956T
1
Roller bearing
70
26-76868
1
2
Oil seal
26-14077
1
Inner oil seal (Fishline cutter seal)
26-12224
1
1
Outer oil seal (Fishline cutter seal)
71
28-30281
1
Key
72
14-79447
1
Tab washer (use with Black Max props)
14-18323
1
Tab washer (use with MC-I props)
73
79448
1
Retainer ring
74
12-835467Q01
1
Thrust hub (use with Black Max props)
56292A4
1
Thrust hub (use with MC-I props)
75
12-31211A3
1
Splined washer
76
14-816629
1
Tab washer
77
11-52707Q1
1
Propeller nut
78
31640Q4
1
Trim tab (2-3/8”)
34127T2
Opt
Trim tab (4”)
79
10-32470
1
Trim tab screw
80
10-30206
1
Screw
81
11-34933
2
Nut
82
13-42351 1
1
Lockwasher
-
26-33144A2
-
Gear housing seal kit
-
46-96148A8
-
Water pump repair kit
-
43-803091T1
3
-
Lower unit rebuild kit
-
43-803090T1
3
-
Seal & bearing kit
Note 1: Contents of seal kit QS-26-33144A2
Note 2: Contents of water pump repair kit QS-46-96148A8
Note 3: Rebuild kit includes all gears, shims, bearings, seals, clutch & prop nut to rebuild upper lower unit
AR: As required