Mercury 8.1S Horizon, Product Applications Manual

Page: 74 / 163

Exhaust System
90-863758060 AUGUST 2006 Page 6A-5
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.
a
7631
a - Hose 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.
13377
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.