Yamaha EF2000iS Service Manual page 240

TURNING ECONOMY SWITCH OFF FAILS TO INCREASE ENGINE SPEED DURING
NO-LOAD OPERATION.
TURNING ECONOMY SWITCH ON FAILS TO DECREASE ENGINE SPEED DURING
NO-LOAD OPERATION.
WHEN ECONOMY SWITCH IS ON, ENGINE SPEED FAILS TO INCREASE UNDER
LOAD.
Check AC output.
GOOD
Check the throttle control motor.
GOOD
Check the economy control switch.
GOOD
Check the connections of the wire harness connec-
tors and couplers, and the wires for an open circuit or
short circuit.
GOOD
Replace the control unit.
THROTTLE CONTROL SYSTEM
NOT GOOD
NOT GOOD
NOT GOOD
NOT GOOD
6-7
TRBL
Refer to "GENERATOR SYSTEM" in
CHAPTER 5.
Replace the throttle control motor.
Replace the economy control switch.
Correct or replace.