Exhaust Risers; Removal; Cleaning; Inspection - Mercury MerCruiser MCM 454 Mag MPI Service Manual

SERVICE MANUAL NUMBER 23

Exhaust Risers

Removal

1. Remove any items attached to the elbows on the engine and carefully lay them aside.
2. Remove fasteners retaining exhaust elbows and risers to manifolds and retain. Remove
3. Remove and discard old gaskets.

Cleaning

1. Clean gasket mating surfaces on elbows, manifolds and risers.

Inspection

1. Inspect sealing surfaces for leakage and / or corrosion

Installation

1. Assemble studs to exhaust manifold and position all gaskets as shown between risers.
2. Position gaskets (REFER TO EXPLODED VIEWS ON FOLLOWING PAGES), install
IMPORTANT: Restrictor gaskets or manifold separator gaskets must be installed in
order shown.
3. Install elbow on riser(s) and studs. Attach using nuts and washers.
NOTE: Drain plugs in risers must be positioned facing flywheel end of engine, unless other-
wise noted.
4. Torque all fasteners, in a diagonal pattern, to 27 lb.ft. (37 N·m).
5. Place spacers between riser plate, if equipped, and fasten with existing nuts. Tighten
6. Reattach and tighten securely all parts previously removed from elbow to appropriate
Index
90-861326--1 MARCH 1999
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Remember their positioning for reassembly later.
exhaust elbows.
a - Inspect These Surfaces
Refer to "Installation Diagrams" at the end of this section.
elbows to risers and attach using nuts and washers from kit. Torque to 23-32 Ft. Lb.
(32-43 N·m).
securely.
position on riser bracket, if equipped.
a
a
RISERS
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