GASOLINE ENGINE 8.1 S INBOARD MODELS
Page 13 of 58
Continuous Downward Slope From Horizontal
Model
Engine
Installation
Angle*
Minimum
Maximum
Down-Angle
Inboard
Fore End
Raised 2
°
11
°
2-5/16 in. (59 mm)
per 12 in. (305 mm)
21
°
4-5/8 in. (117 mm)
per 12 in. (305 mm)
Down-Angle
Inboard
Fore End
Raised 4
°
13
°
2-3/4 in. (70 mm)
per 12 in. (305 mm)
23
°
5-1/16 in. (129 mm)
per 12 in. (305 mm)
Down-Angle
Inboard
Fore End
Lowered 7
°
16
°
3-7/16 in. (87 mm)
per 12 in. (305 mm)
26
°
5-7/8 in. (149 mm)
per 12 in. (305 mm)
V-Drive
Inboard
Fore End
Lowered 2
°
7
°
1-1/2 in. (38 mm)
per 12 in. (305 mm)
17
°
3-11/16 in. (94 mm)
per 12 in. (305 mm)
V-Drive
Inboard
0
°
9
°
1-7/8 in. (48 mm)
per 12 in. (305 mm)
19
°
4-1/8 in. (105 mm)
per 12 in. (305 mm)
V-Drive
Inboard
Fore End
Raised 3
°
12
°
2-1/2 in. (64 mm)
per 12 in. (305 mm)
22
°
4-7/8 in. (124 mm)
per 12 in. (305 mm)
* Fore - End of engine closest to bow of boat.
•
The first 18 in. (457 mm) of exhaust hose should drop the specified minimum relative to
horizontal. Thereafter, 3
°
of drop or 1/2 in. (13 mm) of drop per 12 in. (305 mm) relative to
horizontal is a MINIMUM requirement for the rest of the exhaust system.
•
Exhaust hoses should not restrict the flow of discharge water from the elbow. The ex-
haust hose cannot be bent more than 5
°
relative to the exhaust elbow outlet as a hot spot
in the hose will occur and burn through.
•
Exhaust outlet must be above the water line with boat at rest in the water and loaded
to capacity.
•
System must not cause excessive back pressure when measured 10 in. (254 mm) aft
of the exhaust elbow outlets. Back pressure MUST NOT exceed 2 psi (14 kPa). Mini-
mum exhaust hose sizes are given in the following chart:
Minimum Exhaust Outlet Hose Size
Model
Single Outlet
Dual Outlet
ALL
5 in. (127 mm)
4 in. (102 mm)
•
Exhaust hoses must be secured at each connection with 2 hose clamps.
•
An exhaust resonator is included with all 496 cid / 8.1L engines. Installation of this kit is
required on 496 MAG and 496 MAG HO sterndrive engines with a through the transom
or through the hull exhaust. MerCruiser strongly recommends the use of this kit on all
other models.
