Exhaust System Installation; General Exhaust System Notes; Exhaust Outlet Measurement Procedure - Mercury Optimax 250 Service Manual

INSTALLATION

Exhaust System Installation

General Exhaust System Notes

1. Exhaust system application must meet ABYC standard P–1 for marine exhaust installa-
tions.
2. The entire exhaust system must meet 190 p.s.i. (1309.99 kPa) burst pressure.
3. All rubberized exhaust system components must meet SAE J–2006 standards for ma-
rine exhaust hoses.
Mufflers must be secured in such a way as to prevent muffler movement during in-
advertent engine backfire. Movement of mufflers may result in exhaust hose loos-
ening which could cause boat sinking due to water intrusion.
4. The mufflers and exhaust hoses must be adequately supported for proper orientation
and to prevent overstressing the exhaust components. The support requirements will
vary with exhaust system design and the amount of G-forces to be encountered.
5. Rubber hose should be connected to pipes with flares or beads or barbs to prevent the
hose from sliding off the pipe under pressure.
6. For additional exhaust system recommendations, see MERCURY publication
90–884386 which covers all jet drive exhaust applications not covered under these
guidelines.

Exhaust Outlet Measurement Procedure

1. Fill all fuel, oil and water tanks to maximum capacity.
2. Add maximum allowable cargo weight to boat in areas where it will be stored.
3. Add 190 lbs. (86 kg) of weight in all locations where each passenger will sit during normal
operation.
4. Using diagrams provided (following), measure to ensure location of muffler outlets.
5. Move load weight and cargo weight to stern of boat to simulate greatest "stern down"
attitude the boat will encounter such as when loading.
6. Recheck muffler outlet measurements.
7. Check exhaust system slope to ensure 5 down hill slope.
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CAUTION
90-888438 JUNE 2002