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13.
Installation Instructions
line. Install riser spacers if necessary.
A minimum of 18” of exhaust hose must be installed between the
exhaust risers and the collector, Y-pipe, muffler or first angular
fitting. This portion of the exhaust hose must have a downward
slope of 1-1/4”/ft. for conventional inboards and a downward
slope of 7/8”/ft. for V-drives. Some OEM installations may
different from these specifications but these installations have
been carefully evaluated by Marine Power and the OEM.
After the first 18” the exhaust system must have a drop of 1/2”/
ft. Measure exhaust riser height as shown. Minimum exhaust riser
height should be 15” on 6.0 and 6.2L engines. All others should
be 13”.
The slope in the exhaust hose and components must be rout-
ed so that no low point exists in the system where water may
be retained. The muffler, collector and exhaust hoses must be
adequately supported for proper routing and to prevent over
stressing the exhaust manifolds and risers.
Internal flappers may be required on naturally aspirated 6.0 and
6.2L engines.
Applications with through transom exhausts must be equipped
with exhaust flappers to prevent the reverse flow of water into the
engine. Exhaust outlets should be above the water line with the
boat at rest to minimize engine back pressure.
Every exhaust connection should be secured with at least 2 hose
clamps. The clamps should be stainless steel and at least 1/2”
wide.
Electrical Connection
NOTE:
Marine Power EFI engines are equipped with “Smart
Start” this feature is common in late model automobiles but is
new to the boating industry. This feature enables the operator
to start the engine by momentarily engaging the key switch, it is
not necessary to hold the key switch. The ECM maintains the start-
er engagement until the engine starts. Once the engine starts,
the ECM prevents the starter from engaging even if the operator
mistakenly turns the key switch. To ensure proper operation of
this feature, the engine wiring harness includes an 18 gauge
wire coiled by the starter. This wire must be connected directly
to the battery or the battery switch. Do not connect this wire to
the starter post as the voltage drops excessively at this location
during starting.
Batteries
Tapered post connections with wing nut connections can be used.
The tapered posts must be used for the engine battery cables
while the wing nut connections should only be used for acces-
sories. We highly recommend that wing nuts be replaced with
regular nuts to increase the tightness of the connections.
Pay particular attention to ground connections. EFI engines are
very dependent on secure ground connections. See typical ground
location.
Dual Engines
Batteries: Vessels with twin engines should have a battery for
each engine. The battery switch should be positioned so each
engine is running off its own battery.
Battery Isolators
Many boats are equipped with auxiliary batteries. Such bat-
teries are used to operate stereos, etc. Battery isolators can be
used to charge an auxiliary battery. In these cases, the alternator
output is connected to the center post on the isolator instead of the
starter. The owner should familiarize himself with the isolator’s
operation.
Engine Battery Specifications
Model
Minimum Required Rating
4.3L
550 CCA
5.3L
650 CCA
6.2L
750 CCA
