A water-cooled exhaust manifold is provided for engines incorporating a heat exchanger cooling system. The
outlet flange may be located at the end or at the mid-section of the exhaust manifold, depending upon the
installation requirements. A flexible exhaust connection or a muffler may be attached to the outlet flange. The
exhaust manifold is attached to studs located between the exhaust ports and the outer side of the two end ports in
the cylinder head. Special washers and nuts secure the manifold to the cylinder head.
Water-Cooled Exhaust Manifold
The one-piece water-cooled manifold is cast with an integral water jacket surrounding the exhaust chamber. The
diameter of the exhaust chamber increases uniformly from one end to the other where it terminates in a flange to
which an elbow and flexible exhaust connection is attached. A portion of the engine coolant is bypassed from the
rear of the cylinder block into the rear end of the jacket surrounding the exhaust manifold and is discharged from
the forward end through a tube into the thermostat housing. A drain cock is installed in the bottom of the manifold
for draining the water jacket. A plug is provided in the bottom of the exhaust manifold elbow for draining moisture
condensed from the exhaust gases.
A normally open ball valve allows raw water exiting the marine gear oil cooler to be pumped into the exhaust
system between the turbochargers and the muffler, filling the muffler with water and cooling prior to being
expelled through the exhaust flapper port with the engine exhaust fumes. In addition to cooling the muffler, the
water also acts as a noise dampening media within the muffler itself.
The engine electrical system consists of a starting motor, a battery-charging alternator, a storage battery, and the
necessary wiring. Additional equipment such as an engine protective system is also included.
The battery-charging circuit consists of an alternator, battery, and the wiring. The battery-charging alternator is
introduced into the electrical system to provide a source of electrical current for maintaining the storage battery in
a charged condition and to supply sufficient current to carry any other electrical load requirements up to the rated
capacity of the alternator.
The hinge-mounted alternating current self-rectifying alternator, mounted on the front of the engine, is belt-driven.
The alternator drive pulley is keyed to a shaft which is coupled to the end of the crankshaft. An adequate
alternator drive ratio is necessary for an engine equipped with extra electrical accessories and one that has to
operate for extended periods at idle speeds. Diodes, built into the slip ring end frame, rectify the three phase AC
voltage to provide DC voltage at the battery terminal of the alternator, thereby eliminating the need for an
The starting motor is mounted on the flywheel housing. When the starting circuit is closed, a small drive pinion on
the armature shaft engages with the teeth on the engine flywheel ring gear to crank the engine. When the engine
starts, the drive pinion disengages to prevent the armature from overspeeding and damaging the starting motor.