Technical Reference Manual
- Recheck all wire connections to be certain they
are clean and tight. Be sure the two plugs are
pushed on properly.
- You must have 12 VDC minimum on the
module "IGN" terminal and the "GND" terminal
must be grounded.
- If the gauge on the dash is always "pegged" to
port or starboard, the module is usually at fault.
It probably will need replacement.
- The module can be checked by measuring
certain voltages while the system is running.
Connect a volt-ohm test meter to the dash
gauge as shown to either port or starboard
side. With both ignitions on (but the engine not
running) the test meter should read about 5
volts either side. At 2,000 RPM on starboard
engine (0 RPM on port), the meter will read
9 volts on starboard side and 2 volts on port.
Repeat the test by swapping actions to the
port engine. NOTE: All voltages listed are
- To check gauge only (Fig. 1), place a 130-ohm
1/2-watt resistor from port or starboard gauge
terminal to ground. Connect the gauge ignition
terminal to positive voltage source. The pointer
will deflect about 45.
- System is energized only when ignition switch it
is connected to is on.
- The gauge pointer will point towards the "faster"
engine, if wired as shown above. Reversing the
"S" and "P" connections at the module will make
the synchronizer point to the "slower" engine.
- In some cases it may be necessary to decrease
the sensitivity of the system. This means a
greater difference of engine speeds will be
required for an equal deflection of the gauge
pointer. Loosen the jumpers, swing them out of
the way, re-tighten nuts.
- One module can operate two gauges, if the
sensitivity jumpers are left in place. Damage
to the module will result if they are removed.
- The same gauge and harness can be used on
various type engines, but the module must be
changed with engine type:
The gauge can be zeroed by adjusting the
module's null potentiometer under the red hole
plug (with both ignitions on).
- PART NO. APPLICATIONS
- 1508370P Gasoline stern drive & inboard
- 1504877 Diesel Alternator
- 1507574 Diesel Magnetic Pickup
- 1508473 Diesel Signaflex