MerCruiser MR/Alpha One Gear Housing Diagram

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