Page 362 - REPOWER REFERENCE GUIDE (2020)

Measuring Exhaust Elbow Height
General Information

The height of the exhaust elbows must be within the dimensions specified to prevent water intrusion problems. Exhaust elbow
risers must be installed, if needed to obtain the proper exhaust elbow height and exhaust angle. Risers are limited to 203 mm
(8 in.) on 8.1L (inboard) and 496 (sterndrive) models and 152 mm (6 in.) on all other models except 3.0L (sterndrive). The
height measurement must be taken with the boat in the water. Load the boat as outlined to simulate the maximum loading
conditions likely to be encountered in normal operation.
IMPORTANT: Exhaust elbow height is measured to the waterline inside of the water lift muffler (instead of the waterline outside
of the boat) on applications so equipped. Refer to Section 7C ‑ Water Lift Muffler.
IMPORTANT: Load distribution recommendations are the responsibility of the boat manufacturer. Any load distribution
conditions that will affect the exhaust system must be clearly communicated to the operator in the owner's manual. For
example, the number of people that can be located on the swim platform simultaneously should be included in the manual if
this could pose a problem.
Measurements under all loading conditions must be within the following specifications.
Minimum Exhaust Elbow Height—Sterndrive

Model Specification
3.0L (181 cid) 279 mm (11 in.)
4.3L (262 cid)
4.5L (275 cid)
5.0L (305 cid) 330 mm (13 in.)
5.7L (350 cid)
6.2L (377 cid)
8.1L (496 cid) 381 mm (15 in.)

Minimum Exhaust Elbow Height—Inboard
Model Specification
MIE and V‑drive TowSport models 381 mm (15 in.)
TowSport in‑line models 330 mm (13 in.)
Minimum Exhaust Hose Slope—Sterndrive or Inboard

Model Specification
4.3L (262 cid) Within 457 mm (18 in.) Remainder of system (if applicable)
4.5L (275 cid)
5.0L (305 cid)
5.7L (350 cid) 10° 3°
6.2L (377 cid)
8.1L (496 cid)
Minimum Exhaust Elbow Height

Model Specification
4.5L MPI ECT, SeaCore 4.5L ECT, and 4.5L Non‑ECT models 279 mm (11 in.)
6.2L MPI ECT, SeaCore 6.2L ECT, and 6.2L Non‑ECT models 279 mm (11 in.)

IMPORTANT: Switchable or through‑the‑transom exhaust is not approved for 4.5L V6 models.
Minimum Exhaust Hose Slope

Specification for the remainder of
Model Specification within 45.7 cm (18 in.) of the engine
system (if applicable)
6.2L MPI ECT and 6.2L Non‑ECT 10° 3°
models
If the exhaust elbow height or exhaust angle is insufficient, modify the exhaust system or install the appropriate exhaust riser.
Refer to the appropriate Mercury Precision Parts and Accessory Guide for part numbers.
The maximum exhaust riser height is specified in the following table.

Page 10A-2 © 2019 Mercury Marine 90-8M0149179 eng NOVEMBER 2018