Genuine Scooter Company Buddy 170, Service Manual

Page: 22 / 137

7. Start-up normal but idle speed unstable during warm-up
General trouble location: 1. Water in fuel; 2. Engine temperature sensor; 3. Spark plug; 4. Air throttle and
idle air bypass; 5. Air intake; 6. Idle governor; 7. Engine mechanism.
Procedure for general diagnoses:
No. Operating Procedure
Detection
Results
Subsequent Steps
Yes
Repair the air intake
system.
1 Check any jam of the air filter and leakage of the air intake.
No Next step
Yes Next step
2
Check the spark plug and its model and gap conformable to
specifications.
No
Adjustment or
change
Yes Clean relevant parts.
3
Remove the Idle governor and check the air throttle, the isc,
and the idle air bypass for any carbon deposition.
No Next step
Yes
Correct circuits or
replace any sensor.
4
Press the engine temperature sensor connector and start the
engine to check any instability of the idle speed during
warm-up of the engine.
No Next step
Yes
Change the defective
nozzle.
5
Disassemble the nozzle and check the nozzle leaking or
blocked, or the flow out of tolerance with a nozzle cleaner &
analyzer.
No Next step
Yes Change fuel.
6
Check fuel and observe any trouble attributed to fuel just
added.
No Next step
Yes
Eliminate any
mechanical trouble of
the engine.
7
Check pressure of the engine cylinder and find any big
difference in pressure.
No Next step
Yes Diagnosis assist
8
Connect an EMS adapter and press the power switch to check
voltages at Pins
1#, 19#, and 29#
; check grounding at Pins
8#
﹐
35
#
and
36#.
No
Repair the relevant
circuits.
18