A22
Tachometer Adapter
A
tachometer “take
-
off is provided on the starboard side of all naturally aspirated engines as an extra cost option.
There is no provision for mechanical tachometer hook
-
up on turbocharged engines. This adapter accommodates
a standard marine tachometer cable with
’/E”
-
18
adaptor nut. Tip of cable core should be
.187”
diameter. Cable
turns on
-
half engine speed in counter
-
clockwise direction.
If mechanical tachometer is not used or if cable is disconnected with engine to be operated for any lengthy period,
the take
-
off should be capped to prevent oil leakage. Suitable cap (or plug to close aperature if take
-
off assembly
is removed) is listed in the parts section of this manual.
It is recommended that a mechanical type tachometer be used only if located relatively close
to
engine. If cable
length exceeds
12
to
14
feet or if many bends are required, an electrical tachometer system should be considered
as much less strain is placed upon the take
-
off assembly. Installations requiring two tachometers should always
use electric instruments.
Electrics
The standard electrical system for Lehman engines is
12
volt,
NEGATIVE
GROUND.
Under no circumstances
should polarity be reversed even for an instant for serious damage to alternator may result.
For special applications, optional electrical systems are available in
12
volt insulated return,
24
volt negative ground
and
24
volt insulated return configurations.
A vee belt drives the alternator from crankshaft pulley. (Note: maintain belt at proper tension see “minor Repairs,
Maintenance and Adjustments”). Alternator has been corrosion
-
treated and has built
-
in silicon rectifier and enclosed
slip- ring design for safe, sparkless, trouble
-
free operation. Transistor type, sealed voltage regulator has no moving
parts and requires no adjustments. Alternator is lubricant packed for life at time of assembly and therefore requires
no external lubrication. All alternators are equipped with a tapping for connection to operate a matching electric
tachometer. (see Fig.
13)
A
special actuating switch located on side
of
engine block behind alternator automatically energizes the alternator
from the battery when engine is started and oil pressure reaches
7
Ibs. Battery is disconnected by this switch when
the engine is stopped. This switch initiates operation of the alternator system without the need of a separate switch
and precludes the possibility of the operator neglecting to turn the charging system on or off.
If
desired, electrical
instruments such as oil gauge, temperature gauge, etc. may be wired to be autmoatically energized when engine
is started.
The starter motor is located on the left side (rear) of engine and requires no attention beyond, maintaining the
electric cable connections clean and tight, the commutator clean and brushes renewed when necessary.
The standard solenoid mounted on the starting motor is a heavy
-
duty type. It must mechanically engage the starter
pinion with the ring gear on flywheel then it must actuate an electric switch to energize the starting motor.
As
the
solenoid is normally energized by a simple push
-
button located at some distance from the starter, relatively heavy
gauge wire is required to transmit the needed amperage. Using small gauge wire can result in insufficient current
reaching the starter solenoid, overheating of wires, insufficient travel of starter pinion and failure of engine to start.
To assure adequate amperage reaching starter solenoid a “piggy
-
back” solenoid is provided with short, heavy
-
gauge
wires connecting the two solenoids. The new solenoid requires comparatively little amperage
so
smaller gauge
wiring is required for connection to pushbutton.
The accompanying diagram indicates basic wiring requirements. Make certain that all connections are clean and
tight. Locate battery as close as practical to the starter. Gauge of battery cables will be dependent upon length,
but should be
NO.
0
minimum. Use
No.
12
gauge or heavier wire for balance of system. Electrical gauges which
require low current draw may be wired to oil pressure energizing switch indicated by
“X
on the diagram.
E
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