Page 196 - REPOWER REFERENCE GUIDE (2020)

Exhaust System Installation Requirements—Sterndrive Applications
Through‑the‑Propeller Exhaust

Through‑the‑Propeller Exhaust Systems
496 MAG and 496 MAG H.O. models are set up from the factory for through‑the‑transom/hull exhaust to provide the optimum
performance output. If noise regulations do not allow the use of above water exhaust, an exhaust pipe kit (98‑8M0117125) and
intermediate elbow kit (44267A03) are available to convert to through‑the‑propeller exhaust. Kits can be used with or without
exhaust elbow risers. Installation instructions are provided in the kits. Through‑the‑propeller exhaust is the recommended
system on all models except 496 MAG and 496 MAG H.O.
IMPORTANT: EU Emissions Certification requires the use of the MerCruiser Y‑pipe on all 496 MAG and 496 MAG H.O.
engines.
NOTE: Internal shutters are provided with this kit.

18468
Exhaust Tube Usage

The transom assembly on the MX 6.2L MPI, 496 MAG, and 496 MAG H.O. are equipped with an exhaust tube to reduce the
exhaust back pressure when using through‑the‑propeller exhaust. It is no longer necessary to install the tube on these models
at the OEM. Lower horsepower models are equipped with a bellows and do not require the use of this tube.

e a - Exhaust tube
b - Clamp
c - "Side" marking
d - Exhaust tube
d e - Grounding clip

c
b
a
8406
• Through‑the‑propeller exhaust utilizing the Y‑pipe is the recommended system on all models except the 496 MAG and 496
MAG H.O.
• Exhaust elbows must be the specified distance above the waterline. Install exhaust risers if necessary. Refer to Measuring
Exhaust Elbow Height section.
• Measuring back pressure is not necessary when utilizing the MerCruiser designed exhaust Y‑pipe and intermediate
components for through‑the‑propeller exhaust.
• Every exhaust hose connection should be secured with at least two hose clamps. The clamps should be stainless steel
and at least 13 mm (1/2 in.) wide. Clamps which rely solely on spring tension should not be used (ABYC Standard).

Page 7C-4 © 2019 Mercury Marine 90-8M0149179 eng NOVEMBER 2018