Yamaha GX1800A Service Manual page 14

Item
ETV failure ETV failed, or open or
control short circuit is
detected in ETV
circuit.
Battery dis- Battery lead is discon-
connection nected during normal
warning operation
Idle speed Throttle lever is in the
control fully closed (idle)
position.
Over revolu- Engine speed exceeds
tion control 7800 r/min.
High intake In a state where
air pressure engine speed has
control exceeded 7550 r/min
and intake pressure is
higher than 177 kPa
(25.7 psi) has lasted
longer than 1.5 sec-
onds.
Knock control When engine speed
exceeds 2000 r/min
after warming up
Condition
• Opening angle of the ETV
• Maximum engine speed is
• Ignition timing is con-
Control is performed using
the same actions as the
ETV failure control.
Engine speed is limited to
1150–1350 r/min.
Ignition is controlled.
Condi-
tion
Normal
Level 1
Level 2
Level 3
Level 4
The throttle valve is limited
from opening more than the
point where the control was
engaged.
Ignition timing is delayed
according to the volume of
knocking
Action
is fixed to the default
opening angle.
limited to approximately
2500 r/min.
trolled.
Action
None
Ignition is cut off
to 1 cylinder.
Ignition is cut off
to 2 cylinders.
Ignition is cut off
to 3 cylinders.
Ignition is cut off
to all cylinders.
11
Remarks
Completely shutting off the
throttle valve will disengage
the control.