Oilguard (Optional) - Husqvarna K 760 Workshop Manual

18
B
C
D
E
STOP
CORRECT
Fuel/oil
Rpm
10.000
F
53

OILGUARD (OPTIONAL)

A
INCORRECT
Fuel/oil
Rpm
3.800
E
b a
OilGuard prevents the machine from running with the wrong
fuel. To operate the function, an oil containing dye, "Husqvarna
OilGuard oil", must be added.
Fuel analysis commences 10 seconds after start-up and con -
tinues for 50 seconds. If OilGuard indicates the wrong fuel, the
engine speed is restricted to 3,800 revolutions per minute.
Function
A winding in the ignition module (A) generates electric current
to OilGuard. The analysis unit has a light emitting diode (B)
which emits a blue light and lights up a light sensitive photo-
transistor (C). The fuel passes between these two units.
The OilGuard oil contains a yellow dye which absorbs the
light from the light-emitting diode. In this mode, the machine is
operating normally.
If the machine is filled with clean petrol or oil of another
manufacture, the light will pass through the fuel and light up
the photo-transistor. An electronic contact breaker function (D)
then prevents the engine from reaching working speed.
Functional test
An acceleration test indicates whether OilGuard is functioning
correctly. It is best to run the test with the blade dismantled.
Warm up the machine. Restart the machine and quickly put into
full throttle mode. If OilGuard is working correctly, for 1.7
seconds after start-up the engine speed should stop at 4,300 rpm
to then rise to maximum revs. If the engine rises straight to
maxi mum revs without delay, the OilGuard unit is not working.
OilGuard plug with seal
The blue plug (E) above the stop button closes the circuit to
OilGuard. The plug can be removed with a screwdriver and
replaced with a non-conducting orange plug (F). OilGuard will
then be put out of operation.
The factory-assembled OilGuard plug (E) contains a blue seal
(a) which breaks if the plug is removed. On reassembly, the seal
is replaced with the grey-coloured spare part (b) which indicates
that the original construction has been changed.
Assembly/cabling
Assembly and routing of cables in the
machine are shown in the illustrations.
In the flywheel air duct, the short-circuit
2
cable is fitted in the upper channel and the
1
power supply cable in the lower channel.
The OilGuard unit is held in position by a
snap-on lock, enclosed. The holder for the
plug is dismantled inwards.
Note: If the OilGuard is to be replaced,
the plug must be removed in order to loosen
the cables.
The fuel hoses are connected as follows:
1. From the fuel tank (the hose is fixed in
the holder).
2. To carburettor.
Power supply – test
Dismantle the filter and cylinder cover.
Connect a meter to an earth point and the
point of measuring (arrow) which is accessible
with a probe. Reading at idling rpm, 20–40 V
alternating current.