Page 255 - REPOWER REFERENCE GUIDE (2020)

8.1L/496/8.2L Triple Catalyst
Exhaust Manifold and Elbow - Sterndrive Models

Torque
Ref. No. Qty. Description Nm lb‑in. lb‑ft
1 2 Exhaust manifold assembly
2 8 Expansion plug
3 2 Cylinder head to exhaust manifold gasket
4 2 Exhaust collector
5 2 Exhaust collector gasket
6 6 Expansion plug
7 4 O2 sensor 50 – 37
8 4 O2 sensor cover 3.5 31 –
9 AR Screw (M6 x 10)
First 27 – 20
8.2L engine
8 Steel screw (0.375‑16 x 1.75) Second 41 – 30
10 Final 54 – 40
8.1L/496 engine
8 31 – 23
Stainless steel screw (M8 x 35)
First 27 – 20
8.2L engine
8 Steel screw (0.375‑16 x 3.0) Second 41 – 30
11 Final 54 – 40
8.1L/496 engine
8 31 – 23
Stainless steel screw (M8 x 70)
12 12 Hex flange screw (M8) 30 – 22
13 2 Sensor assembly 8 71 –
14 1 O‑ring (1.78 mm x 0.08 mm)
15 2 Clip
19 Screw (M8 x 35) (1A351717 and below) 27 – 20
16
20 Screw (M8 x 35) (1A351718 and above) 27 – 20
17 1 Coolant reservoir bracket stud (M8) (1A351717 and below) 27 – 20
18 2 Screw (M8 x 16)
19 6 Catalyst
20 6 Catalyst retention ring
1 2 in. exhaust elbow kit (contains 2 elbows and manifold to elbow
hose)
4 in. exhaust elbow kit (contains 2 elbows and manifold to elbow
21 1 hose)

6 in. exhaust elbow kit (contains 2 elbows and manifold to elbow
1
hose)
22 2 Gasket
23 2 Screw (M6 x 12)
24 1 Coolant reservoir bracket nut (M8) (1A351717 and below)

90-8M0149179 eng NOVEMBER 2018 © 2019 Mercury Marine Page 7G-7