North Wing S-LSA Maintenance Manual
Model: Scout 912
Version 3.2
Release date 04-16-2014
Page 63
4.5 Electrical System
The wiring schematic for the electrical system is shown on the following page for the Scout
912 model. The Rotax 912 engine outputs a maximum of 250 watts of electrical power from
the lighting coils inside the engine. These coils produce a crude AC power source that must
be rectified and regulated by the Ducati Rectifier/Regulator mounted on the side of the Hot
Box. All power is fused and distributed through either the hot box or the relay/fuse box
terminals shown in the middle of the schematic and hard wired leads to the engine. Note
particularly that the starter solenoid is located inside the Hot Box. The fused supply terminals
are the top three left hand terminals where the fuse amperage is indicated.
Although the lighting coils are capable of outputting 250 watts of power, it is advisable to
restrict the continuous power consumption to about 225 watts. This amounts to about 18.75
amps of electrical load. Otherwise, the lighting coils may overheat and be damaged. The cost
of the coils alone is quite expensive plus the time and expense to tear down the electrical end
of the engine to replace the coil assembly. The lighting coils cannot be individually replaced.
Instead, the entire set of lighting and ignition coils must be replaced as a single unit.
Operation at the full 250 watts for short periods of time is acceptable and should not damage
the coils.
For miscellaneous accessories, a power socket is provided on the instrument panel that will
accommodate up to approximately an 8 amp load allowing about 2 amps for the fuel gauge.
These share the same 10amp fuse. Accessories can be hardwired into the Hot Box provided
they do not exceed the fuse limits. All hard wired accessories must be connected to one of the
three fused terminals. NEVER hardwire any electrical equipment directly to the incoming line
from the engine lighting coils. This is AC and is a “dirty” unregulated power that will damage
electrical equipment. Also, NEVER hard wire any electrical device directly to the output of
the voltage regulator. An excessive un-fused load can damage the Regulator requiring an
expensive repair that could have been avoided.
The Electronic Instrument System (EIS) has a pre-wired cable for the EGT and CHT
temperature probes. The wiring schematic excerpted from the EIS documentation is shown on
the second schematic following this page.
Repairs to the electrical system are limited to replacing broken wires, voltage regulator, starter
solenoid, ignition switch, magneto switches, battery, and lights.
