PGO Tigra AF-125BAE User manual

1
PREFACE
This service manual contains chief instructions in connection with service and
maintenance of PGO TIGRAmotorcycle and is also one technical manual and one
best guideline illustrating details for service workers who are engaged in maintenance,
reparation, replacement of parts, troubleshooting, and reassembly. The service manual
prepared from simple takedown to detailed disassembly and from performance
introduction to service preparation provides complete instructions for general
lubrication and routine check or adjustment. Explained with general views, exploded
views, or photos, all necessary items repeatedly cited should be referred to the
previous drawings and not further described in detail herein.
As a result of this service manual composed of directions for the following model,
please check the model of your motorcycle among different ones in the manual for
any contents available.
AF-125BAE: Four-Stroke Cycle, 125CC Level, 4-valve, water cooling,
electronic injection engine
The high-performance electronic fuel-injected water-cooling engine provided in
this motorcycle is the up-to-date 125CC engine developed by Motive Power and being
excellent in the engine kept within the optimal operating temperatures for high
precision and the power output superior to that of a general air-cooling engine.
For any inadvertent mistakes attributed to preparation in a hurry, Motive Power
Industry sincerely wish any person skilled in the art offer any comments.
MOTIVE POWER INDUSTRY CO., LTD.

Contents
2
This manual is a service manual for PGO Tigra Series with details specifying
skills to disassemble or install various mechanisms, basic maintenance (check and
adjustment) of components, notices for operation, and configuration of colored
electrical wires in connection with the motorcycle in which there are 5 chapters and
10 sections as references of users or mechanics during service.
Classification Detail Item Page
Information
summary and
preparation
Specification, code of practice, torque
meter, service instruction
1 1~22
External Installation or removal of external
components
2 23~28
Engine
Check & adjustment
3 29~39
Lubrication system 4 40~42
Disassembly of an engine 5 43~50
Cooling system 6 51~58
Fuel injection system 7 59~71
Instructions of operating the diagnosis
system (PC version)
8 72~83
Exhaust system Exhaust control system 9 84~86
Circuit
diagrams Index of circuits and colored wires for vehicle
10 87~88

3
1-1 Configuration
Water tank / fan
Auxiliary water tank
Front brake disk
Front brake caliper Drain plug bolt (engine oil)
Engine oil filter
Drain plug bolt
(gear oil)
Gear oil
Filling orifice bolt
Shutter magnetic lock
Seat / Oil tank switch
Variable voltage rectifier
Rear brake caliper
Rear brake disk
Air filter
Filler hole (auxiliary water tank)
Movable step
Oil meter
Water pump
Horn
Exhauster
Warning lamp switch
Start button
Front lamp switch
High / low beam switch
Over-speed lamp switch
Signal lamp switch (L & R)
Horn button
Battery / fuse
Diagnosis connector
Oil tank cover
Spark plug
Start / ECU relay
ECU
Ignition coils
Exhauster

InformationSummaryandPreparation 1
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1-2 Positions of engine number / vehicle identification number:
Engine number
Vehicle identification number

InformationSummaryandPreparation 1
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1-3 Specifications: (以下表格內容不需翻譯)
國產機器腳踏車規格表
廠牌摩特動力車架(身) 鋼管
型式AF-125BAE 懸吊前伸縮式
尺全長1865
mm 裝置後整體搖擺式
全寬710
mm 傳一次減速裝置 0.8~2.34
全高1140
mm 動二次減速裝置 43/15*42/13=9.262
度軸距1300
mm 裝離合器乾式離心重錘式
空前48 ㎏置變速器V皮帶式 C.V.T
重後74 ㎏輪胎尺寸及 前110/70-12
重合計128 ㎏層數(p.r) 後130/70-12
乘坐人數或載重 2 人(150 ㎏) 煞前碟式
車後碟式
量
前燈(遠. 近光) 12V-60W/55W
性最高速率105 km/hr 燈後燈/牌照燈 12V-0.4W/12V-5W
耗油率42 km/L 光煞車燈12V-2W
能爬坡能力26°以上 方向燈(前/後) 12V-2W/12V-2W
型式A1 喇叭直流 12V
使用燃料95 無鉛汽油 消音器密閉擴散吸收式
引循環數及冷卻方式 四行程水冷 排氣 粒狀污染物 15 %以下
汽內徑φ52.4 mm 放濃 一氧化碳 3.0%以下
行程57.8 mm 廢度 碳氫化合物 1600 ppm 以下
缸缸數及排列 單缸排氣口位置及方向 後架下引擎右側朝後
總排氣量124.6 c.c. 潤滑方式壓送飛濺並用
壓縮比11: 1 E. E. C. 有
最大馬力* P. C. V. 有
最大扭力* 觸媒有
擎安裝位置及方式 座墊下水平式 汽油箱容量6.8 公升
點火方式電晶體電子點火
起動方式電動起動
備
註1. 銷售名稱: TIGRA

InformationSummaryandPreparation 1
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1-4 Code of practice:
1. Any clamp or cotter pin removed shall be replaced with a new one.
2. Any part to be replaced shall be manufactured by Motive Power.
3. Make sure of any assembled component securely fastened and formally activated.
4. Any bolts or nuts with large external diameters rather than small ones shall be screwed first and
diagonally according to rated torque values as follows.
5. Any mechanic shall use specific or common tools for any disassembly and wear work shoes during
maintenance.
6. The safety of any maintenance operation practiced by two mechanics shall be ensured each other.
7. Any electrical parts slightly heated with the motorcycle started are normal and not touched by hands
directly.
8. Please keep any cable or wire harness to be installed properly fixed but not excessively tensioned or
loosened without any acute (or sharp) angle or bulged bolt (or screw) piercing a cable. Check any
cable or wire harness installed for any unnecessary twist or kink.
9. Do not put any tool on the motorcycle, particularly the battery unit to become a short circuit, during
maintenance.
10. The battery in a motorcycle which has not been started for a long period shall be tested once to ensure
its voltages and charged per month.
11. Please follow the correct steps to connect and disconnect a lead acid battery without the short circuit
or inflammation.
1-4-1 Directions for maintenance of the Engine Management System (EMS)
1) Directions for General Maintenance
Any check to the Electronic Management System shall be made with a multi-meter only.
1. To make sure of the Electronic Management System properly running, please use parts supplied by
Motive Power during maintenance.
2. Any operation to clean parts during maintenance shall be executed in a well-ventilated place.
3. Please follow the directions for steps of maintenance and diagnosis.
4. Do not disassemble or remove parts in the Electronic Management System during maintenance.
5. Please keep watch for any electronic element (electronic control unit, sensor, etc.) not fallen to the
ground during maintenance; establish the environmental protection concept for any waste from
maintenance invalidly disposed.
2) Directions during maintenance
1. Do not arbitrarily remove any part or connector of the Electronic Management System from its
initial position; avoid any accidental damage or foreign object such as water and greasy dirt to
enter into any connector and affect a properly running Electronic Management System.
2. In order to prevent any electrical device from damage, the power supply shall be disconnected

InformationSummaryandPreparation 1
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prior to a connector removed or connected.
3. During any operation to simulate the thermal state of one defective unit or increase temperatures,
the temperature of the electronic control unit shall be less than 80 degrees Celsius.
4. All fuel hoses shall be high pressure-tolerant pipes in virtue of the high fuel pressure in the
Electronic Management System (300kPa or so) or even at the engine stopped. As a result, the fuel
hose during maintenance shall not be disassembled arbitrarily. In the case of maintaining the fuel
system, the pressure in the fuel system shall be released prior to removal of a fuel hose shown as
follows: Remove the fuel pump relay; start the engine; keep the engine at the idle speed until the
engine stops. The operation of removal of a fuel hose and replacement of a clamp shall be
executed by a professional mechanic in a well-ventilated place.
5. The power supplied to the electric fuel pump which is being removed from the fuel tank shall be
disconnected beforehand to prevent any spark or fire.
6. The fuel pump to be tested shall not be empty or refilled by water or the service life will be
curtailed. On the other hand, the positive and negative poles of the fuel pump shall be properly
connected.
7. Unless otherwise required, the spark test shall not be conducted or be completed quickly during
inspections of the ignition system. Additionally, the air throttle shall be kept closed during
inspections or the incompletely ignited gasoline will be fed into the exhauster and damage the
three-way catalytic converter.
8. The idle speed has been adjusted by the Electronic Management System in advance and not
changed manually. The initial position of the throttle stop screw adjusted by Motive Power shall
not be changed by a user without permission unless otherwise demanded.
9. The cables to be connected to the positive and negative poles on a battery shall be correctly linked
or the electronic devices will be damaged. The minus earth is used in the system.
10. Any cable connected to a battery shall not be disconnected during the engine running.
11. The battery shall be removed from the motorcycle for a charge separately conducted but not be
directly charged with the battery fixed on the vehicle for convenience.
12. The cables connected to the battery’s positive & negative poles and the electronic control unit
shall be removed from the motorcycle prior to any electrical welding operation.
13. Do not cut a cable’s cover layer to test any signal imported to or exported from one device.
1-5 Torque
Rated values
Type Torque (kg-m) Type Torque (kg-m)
5mm bolt 0.4~0.5kg-m 6mm nut 1.0~1.4kg-m
6mm bolt 0.9~1.1kg-m 8mm nut 2.0~3.0kg-m
8mm bolt 1.8~2.5kg-m 10mm nut 3.0~4.0kg-m
10mm bolt 3.0~4.0kg-m Pin / bolt 1.5~2.0kg-m
12mm bolt 5.0~6.0kg-m

InformationSummaryandPreparation 1
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Body / Engine
Type Torque (kg-m) Type Torque (kg-m) Type Torque (kg-m)
Disk
Front axle
Brake caliper
Joint bolt (brake hose)
Brake pump assembly
Drain plug bolt (engine oil)
Drain plug bolt (gear oil)
Oil screen cover
Fixed rotor
Crank angle sensor
Drive propeller (water pump)
Engine temperature sensor
Temperature controller
2.0-2.5
5.0-6.0
2.0-3.0
3.5±0.2
0.8-1.2
1.2-1.8
2.5-3.0
1.5-2.0
0.9-1.1
0.7-0.9
1.0-1.4
1.53
0.9-1.1
Flywheel
Cylinder head - nut
Cylinder head - screw
Crank case cover (right)
Gear box nut
Rear axle
Camshaft sprocket
Cylinder head cover
Oil pump
Flywheel & one-way clutch
Gear box
Stud bolt (cylinder head)
Crank case (left & right)
5.0-6.0
2.0-2.4
0.9-1.1
0.9-1.1
5.0-6.0
10.0-11.0
2.2±0.2
1.0-1.2
0.9-1.1
2.8-3.2
2.5-2.8
0.9-1.1
0.9-1.1
Handlebar
Engine hanger
Front shock absorber
Rear shock absorber
Exhauster (Front)
Exhauster (Rear)
Rear fork
Oxygen sensor
Left side cover
Center stand
Support (Center stand)
Leaking bolt (brake caliper)
4.5-6.0
2.4-3.0
3.5-4.5
1.5-1.8
3.0-3.5
3.0-3.5
4.0-6.0
0.9-1.1
3.5-4.0
2.5-2.8

InformationSummaryandPreparation 1
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1-6 Service tools
Summary of service tools
Tool name: Electronic Management System diagnosis tester
(EMS diagnosis system)
Functions: Read / delete PCODE of EMS; check data & process, and test
parts’ functions.
測試等。
Tool name: Multi-meter
Functions: Check voltage, current, and resistance of EMS.
Tool name: Fuel pressure gauge
Functions: Check pressures of the fuel system; determine
status of the fuel pump and the fuel pressure governor in the
fuel system.
Tool name: Cylinder pressure gauge
Functions: Check each cylinder’s pressure.
Tool name: Leak detector (water cooling system)
Functions: Test any leakage of the water cooling system to
keep the system well sealed.
Tool name: Flywheel withdrawal kit
Functions: Disassemble the flywheel assembly

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Tool name: Water pump shaft SC seal kit
Functions: Install SC seals on the water pump shaft
Tool name: Mechanical seal kit
Functions: Install the mechanical seal.
Tool name: Crank bearing withdrawal kit
Functions: Disassemble and separate the crank
bearing.
Tool name: Snap-fit kit
Functions: Remove or install a snap-fit of the cooling
water hose or high-pressure fuel hose
Tool name: Crank extraction kit
Functions: Extract the crank from the case.
Tool name: Crank installation kit
Functions: Install the crank on the case.

InformationSummaryandPreparation 1
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1-7 Procedure to maintain the Electronic Management System (EMS)
Systematic procedure to diagnose any troubles for reparation
Items to be checked first prior to any diagnoses for engine troubles:
1. Make sure of the engine trouble indicator normally running;
2. Check with a trouble diagnosis meter to ensure no trouble information recorded;
3. Check any trouble phenomenon hinted by the vehicle owner and trouble-related conditions.
External check:
(1) Check any leakage from a fuel hose.
(2) Check any leakage from a vacuum pipe.
(3) Check any jam, leakage, flattening, or damage at an air inlet.
(4) Check the ignition system for break or aging of any high-voltage cable and ignition status.
(5) Check grounding of any wire harness clean and securely fixed.
(6) Check any sensor or actuator’s connector loosened or poorly contacted.
Note: Repair any trouble specified herein first which may affect the subsequent diagnoses or
reparation.
Diagnosis assist:
1. Make sure of no engine-related trouble records;
2. Make sure of any offered troubles;
3. Follow the said procedure to complete inspections and find no any unconformable situation;
4. Do not ignore any effect from maintenance, cylinder pressure, mechanical timing, or fuel on the
system;
5. Replace ECU for tests.
In the event of any trouble eliminated, ECU should be the source of trouble; if not, install the
original ECU and repeat the procedure to recheck.
Trouble:
Engine not running or slowly running during start-up
Engine running but start-up failing during start-up
Trouble of hot start
Trouble of cold start
Trouble of start-up anytime despite RPM normal
Start-up normal but idle speed unstable anytime
Start-up normal but idle speed unstable during warm-up
Start-up normal but idle speed unstable with warm-up finished
Start-up normal but idle speed unstable or stall with load such as front lamp applied
Start-up normal but idle speed too high
RPM low or stall during acceleration
Acceleration slow
Acceleration powerless; performance bad

InformationSummaryandPreparation 1
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(1) Engine not running or slowly running during start-up
General trouble location: 1. Battery; 2. Start motor; 3. Main wiring or power switch; 4. Engine
mechanism.
Procedure for general diagnoses:
No. Operating Procedure Detection
Results Subsequent Steps
1
Check the voltage between two battery terminals with a
multi-meter to ensure the voltage between 11 and 12V
during start-up of the engine.
Yes Next step
No Replace the battery.
2 Keep the power switch “ON” and check the voltage at the
positive terminal on the start motor over 8V.
Yes Next step
No Fix or replace wiring
harness.
3 Remove the start motor and check its status for open
circuits or jam attributed to lubrication insufficient.
Yes Fix or replace the start
motor.
No Next step
4 For any trouble in winter only, check lubricant in the engine
wrong for big resistance of the start motor.
Yes Change applicable
lubricant.
No Next step
5 Check mechanical resistance inside the engine causing the
motor not running or slowly running.
Yes Correct resistance inside
the engine.
No Repeat the said step.
(2) Engine running but start-up failing during start-up
General trouble location: 1. Oil tank empty; 2. Fuel pump; 3. RPM sensor; 4. Ignition coils; 5. Engine
mechanism.
Procedure for general diagnoses:
No. Operating Procedure Detection
Results Subsequent Steps
1
Connect a fuel pressure gauge before the fuel inlet of the
nozzle; press the power switch repeatedly if necessary or start
the engine to check the fuel pressure at 300kPa or so.
Yes Next step
No Repair the fuel supply
system.
2 Connect the EMS diagnosis tester and check “Engine RPM”;
start the engine to check any RPM signal output.
Yes Next step
No Correct circuits of the
RMP sensor.
3 Disconnect the ignition cable and connect a spark tester; start
the engine and check any high-voltage flash (blue/white).
Yes Next step
No Repair the ignition
system.
4 Check pressure of the engine cylinder and find any possibility
of pressure insufficient.
Yes
Eliminate any
mechanical trouble of
the engine.
No Next step
5
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2#
and 21#.
Yes Diagnosis assist
No Repair the relevant
circuits.

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(3) Trouble of hot start
General trouble location: 1. Water in fuel; 2. Fuel pump; 3. Engine temperature sensor; 4. Ignition coils
Procedure for general diagnoses:
No. Operating Procedure Detection
Results Subsequent Steps
1 Connect a fuel pressure gauge before the fuel inlet of the nozzle;
start the engine to check the fuel pressure at 300kPa or so.
Yes Next step
No Repair the fuel
supply system.
2 Disconnect the ignition cable and connect a spark tester; start the
engine and check any high-voltage flash (blue/white).
Yes Next step
No Repair the
ignition system.
3
Press the engine temperature sensor connector and start the
engine; check if the engine successfully started. (Or install a
series-connected resistor (300Ω) in lieu of the engine
temperature sensor at the engine temperature sensor
connector. Check if the engine is successfully started.)
Yes
Correct circuits
or replace the
sensor.
No Next step
No Next step
4 Check fuel and observe any trouble attributed to fuel just added. Yes Replace fuel.
No Next step
5
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2#
and 21#.
Yes Diagnosis assist
No Repair the
relevant circuits.

InformationSummaryandPreparation 1
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(4) Trouble of cold start
General trouble location: 1. Water in fuel; 2. Fuel pump; 3. Engine temperature sensor; 4. Nozzle; 5.
Ignition coils; 6. Air throttle and & idle air bypass; 7. Engine mechanism.
Procedure for general diagnoses:
No. Operating Procedure Detection
Results Subsequent Steps
1
Connect a fuel pressure gauge before the fuel inlet of the
nozzle; start the engine to check the fuel pressure at 300kPa
or so.
Yes Next step
No Repair the fuel system.
2
Disconnect the ignition cable and connect a spark tester;
start the engine and check any high-voltage flash
(blue/white).
Yes Next step
No Repair the ignition system.
3
Press the engine temperature sensor connector and start the
engine; check if the engine successfully started. (Or install
a series-connected resistor (2500Ω) in lieu of the engine
temperature sensor at the engine temperature sensor
connector. Observe if the engine is successfully started.)
Yes Correct circuits or replace
any sensor.
No Next step
4 Slightly pull the throttle to check if the engine is easily
started.
Yes Clean the air throttle and
the idle air bypass.
No Next step
5 Disassemble the nozzle and check any leakage or jam in
the nozzle with a nozzle cleaner & analyzer.
Yes Replace the defective
nozzle.
No Next step
6 Check fuel and observe any trouble attributed to fuel just
added.
Yes Change fuel.
No Next step
7 Check pressure of the engine cylinder and find any
possibility of pressure insufficient.
Yes Eliminate any mechanical
trouble of the engine.
No Next step
8
Connect an EMS adapter and press the power switch to
check voltages at Pins 5#, 10#, and 23#; check grounding
at Pins 2# and 21#.
Yes Diagnosis assist
No Repair the relevant circuits.

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(5) Trouble of start-up anytime despite RPM normal
General trouble location: 1. Water in fuel; 2. Fuel pump; 3. Engine temperature sensor; 4. Nozzle; 5.
Ignition coils; 6. Air throttle and & idle air bypass; 7. Air intake; 8. Ignition timing; 9. Spark plug; 10.
Engine mechanism.
Procedure for general diagnoses:
No. Operating Procedure
Detection
Results Subsequent Steps
1 Check any jam of the air filter and leakage of the air intake. Yes Repair the air intake
system.
No Next step
2
Connect a fuel pressure gauge before the fuel inlet of the
nozzle; start the engine to check the fuel pressure at 300kPa or
so.
Yes Next step
No Repair the fuel supply
system.
3 Disconnect the ignition cable and connect a spark tester; start
the engine and check any high-voltage flash (blue/white).
Yes Next step
No Repair the ignition
system.
4 Check the spark plug in the cylinder and its model and gap
conformable to specifications.
Yes Next step
No Adjust or change the
spark plug.
5 Press the engine temperature sensor connector and start the
engine; check if the engine is successfully started.
Yes Correct circuits or
replace the sensor.
No Next step
6 Slightly pull the throttle to check if the engine is easily started. Yes
Clean the air throttle
and the air intake for
idle speed.
No Next step
7 Disassemble the nozzle and check any leakage or jam in the
nozzle with a nozzle cleaner & analyzer.
Yes Change the defective
nozzle.
No Next step
8 Check fuel and observe any trouble attributed to fuel just
added.
Yes Change fuel.
No Next step
9 Check pressure of the engine cylinder and find any possibility
of pressure insufficient.
Yes
Eliminate any
mechanical trouble of
the engine.
No Next step
10 Check if mechanical ignition timing of the engine is
conformable to specifications.
Yes Next step
No Correct ignition
timing.
11
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2#
and 21#.
Yes Diagnosis assist
No Repair the relevant
circuits.

InformationSummaryandPreparation 1
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(6) Start-up normal but idle speed unstable anytime
General trouble location: 1. Water in fuel; 2. Nozzle; 3. Spark plug; 4. Air throttle and idle air bypass;
5.Air intake; 6. Idle governor; 7. Ignition timing; 8. Spark plug; 9. Engine mechanism.
Procedure for general diagnoses:
No. Operating Procedure Detection
Results Subsequent Steps
1 Check any jam of the air filter and leakage of the air intake. Yes Repair the air intake
system.
No Next step
2 Check the Idle governor for the control valve jammed. Yes Ch an ge
No Next step
3 Check the spark plug and its model and gap conformable to
specifications.
Yes Next step
No Adjustment or change
4 Check the air throttle and the idle air bypass for any carbon
deposition.
Yes Cleaning
No Next step
5 Disassemble the nozzle and check any leakage or jam in the
nozzle with a nozzle cleaner & analyzer.
Yes Replace the defective
nozzle.
No Next step
6 Check fuel and observe any trouble attributed to fuel just added. Yes Change fuel.
No Next step
7 Check pressure of the engine cylinder and find any big difference
in pressure.
Yes
Eliminate any
mechanical trouble of the
engine.
No Next step
8 Check if mechanical ignition timing of the engine is conformable
to specifications.
Yes Next step
No Correct ignition timing.
9
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2# and
21#.
Yes Diagnosis assist
No Repair the relevant
circuits.

InformationSummaryandPreparation 1
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(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
1 Check any jam of the air filter and leakage of the air intake. Yes Repair the air intake
system.
No Next step
2 Check the spark plug and its model and gap conformable to
specifications.
Yes Next step
No Adjustment or
change
3 Remove the Idle governor and check the air throttle, the idle
governor, and the idle air bypass for any carbon deposition.
Yes Clean relevant parts.
No Next step
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.
Yes Correct circuits or
replace any sensor.
No Next step
5
Disassemble the nozzle and check the nozzle leaking or
blocked, or the flow out of tolerance with a nozzle cleaner &
analyzer.
Yes Change the defective
nozzle.
No Next step
6 Check fuel and observe any trouble attributed to fuel just
added.
Yes Change fuel.
No Next step
7 Check pressure of the engine cylinder and find any big
difference in pressure.
Yes
Eliminate any
mechanical trouble of
the engine.
No Next step
8
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2#
and 21#.
Yes Diagnosis assist
No Repair the relevant
circuits.

InformationSummaryandPreparation 1
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(8) Start-up normal but idle speed unstable with warm-up finished
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
1 Check any jam of the air filter and leakage of the air intake. Yes Repair the air intake
system.
No Next step
2 Check the spark plug and its model and gap conformable to
specifications.
Yes Next step
No Adjustment or
change
3 Remove the idle governor and check the air throttle, the idle
governor, and the idle air bypass for any carbon deposition.
Yes Clean relevant parts.
No Next step
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.
Yes Correct circuits or
replace any sensor.
No Next step
5 Disassemble the nozzle and check the nozzle leaking or blocked, or
the flow out of tolerance with a nozzle cleaner & analyzer.
Yes Change the defective
nozzle.
No Next step
6 Check fuel and observe any trouble attributed to fuel just added. Yes Change fuel.
No Next step
7 Check pressure of the engine cylinder and find any big difference
in pressure.
Yes
Eliminate any
mechanical trouble
of the engine.
No Next step
8
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2# and
21#.
Yes Diagnosis assist
No Repair the relevant
circuits.

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(9) Start-up normal but idle speed unstable or stall with load such as front lamp applied
General trouble location: 1. Idle governor; 2. Nozzle.
Procedure for general diagnoses:
No. Operating Procedure Detection
Results Subsequent Steps
1 Remove the idle governor and check the air throttle, the idle
governor, and the idle air bypass for any carbon deposition.
Yes Clean relevant parts.
No Next step
2
Check if the engine’s output power is increased with the load
applied; use the EMS diagnosis tester to check any change in
the ignition advance angle, duration of fuel injection, and air
input.
Yes Go to Ste p 4.
No Next step
No Repair the air
regulating system.
3
Disassemble the nozzle and check the nozzle leaking or
blocked, or the flow out of tolerance with a nozzle cleaner &
analyzer.
Yes Change the defective
nozzle.
No Next step
4
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2#
and 21#.
Yes Diagnosis assist
No Repair the relevant
circuits.

InformationSummaryandPreparation 1
20
(10) Start-up normal but idle speed too high
General trouble location: 1. Air throttle and idle air bypass; 2. Vacuum tube; 3, Idle governor; 4. Engine
temperature sensor; 5. Ignition timing.
Procedure for general diagnoses:
No. Operating Procedure Detection
Results Subsequent Steps
1 Check the throttle cable for jammed or too tight. Yes Adjustment
No Next step
2 Check the air intake system and the connected vacuum tube
for any leakage.
Yes Repair the air intake
system.
No Next step
3 Remove the idle governor to check the air throttle, the idle
governor and the idle air bypass for any carbon deposition.
Yes Clean relevant parts.
No Next step
4 Press the engine temperature sensor connector and start the
engine; check if the engine’s the idle speed is too high.
Yes Correct circuits or
replace any sensor.
No Next step
5 Check if mechanical ignition timing of the engine is
conformable to specifications.
Yes Next step
No Correct ignition
timing.
6
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2#
and 21#.
Yes Diagnosis assist
No Repair the relevant
circuits.