Evinrude 4906B 4HP 1969, Owner'S Manual

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6
ELECTRICAL
6-1 INTRODUCTION
The battery, gauges and horns, charging
system, and the cranking system are all
considered subsystems of the electrical sys-
tem. Each of these units or subsystems will
be covered in detail in this chapter begin-
ning with the battery.
All engines covered in this manual use
the magneto ignition system and a battery is
not required to operate the engine. Most of
the larger horsepower units use a cranking
motor for starting and the battery is only
used to supply power for this motor.
The starting circuit consists of a crank-
ing motor and a starter-engaging mecha-
nism. A solenoid is used as a heavy-duty
switch to carry the heavy current from the
battery to the starter motor. The solenoid
is actuated by turning the ignition key to
the START position. On some models, a
pushbutton is used to actuate the solenoid.
These engines are also equipped with a
hand starter for use when the electric start-
er motor system is inoperative.
6-2 BATTERIES
The battery is one of the most important
parts of the electrical system. In addition
to providing electrical power to start the
engine, it also provides power for operation
of the
the running lights, radio, electrical
accessories, and possibly the pump for a bait
tank.
Because of its job and the consequences,
(failure to perform in an emergency) the
best advice is to purchase a well-known
brand, with an extended warranty period,
from a reputable dealer.
The usual warranty covers a prorated
replacement policy, which means you would
be entitled to a consideration for the time
left on the warranty period if the battery
should prove defective before its time.
Do not consider a battery of less than
70-ampere hour capacity. If in doubt as to
how large your boat requires, make a liberal
estimate and then purchase the one with the
next higher ampere rating.
MARINE BATTERIES
Because marine batteries are required to
perform under much more rigorous condi-
tions than automotive batteries, they are
constructed much differently than those
used in automobiles or trucks. Therefore, a
marine battery should always be the No. 1
unit for the boat and other types of batter-
ies used only in an emergency.
Marine batteries have a much heavier
exterior case to withstand the violent
pounding and shocks imposed on it as the
boat moves through rough water and in
extremely tight turns.
The plates in marine batteries are thick-
er than in automotive batteries and each
A fUlly charged battery, filled to the proper level
with electrolyte, is the heart
of
the ignition system.
Engine starting and efficient performance can never be
obtained if the battery is below
a
fully charged rating.