Exhaust Through-Hull Fittings; Exhaust Resonators - Mercury MerCruiser Product Applications Manual

Secure all exhaust connections, including those at the exhaust elbow, with two hose
clamps. ABYC standards also specify the use of stainless steel clamps with a
minimum 13 mm (1/2 in.) band width. Do NOT use spring tension clamps.
Exhaust Through‑Hull Fittings
Exhaust fittings (flanges, outlets) must be equipped with an internal shutter and external
flapper to prevent water intrusion problems. This is a requirement on all applications except
water lift mufflers, where it is still recommended. A variety of fittings is available through
Mercury Precision Parts and Accessories.
NOTE: For exhaust accessories, refer to Section 10 — Miscellaneous Accessories.

Exhaust Resonators

The design of the exhaust pipe and muffler system can cause a tuning effect that can
contribute to a water intrusion problem. This tuning effect can be caused by a combination
of factors, including but not limited to:
• Configuration of the exhaust outlets.
• Design and size of the muffler (if applicable).
• Length of exhaust hoses.
• Amount of back pressure in the system.
90-863758060 AUGUST 2006
a
a - Hose clamps
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Exhaust System
Page 6A-5