O.S. engine GF40U-FI User manual

2021.08.01
O.S. ENGINES MFG. CO., LTD.
4 stroke gasoline engine for UAV
GF40U-FI
With EC11 (ECU)
INSTRUCTION MANUAL
version 2.46E

6-15 3-Chome Imagawa Higashisumiyoshi-ku
Osaka 546-0003, Japan
TEL.[phone]
FAX.[phone]
http://www.os-engines.co.jp
・Recommended propellers are 18x6-12，19x6-10，20x6-8 (DxP Inch). We recommend a propeller whose
rpm is within range of 7500rpm～9000rpm at full throttle.
・Start the engine with a safety stick or an electric starter (recommendation for safety reason).
・Periodical inspection after 50, 100 hours are necessary. Follow the maintenance manual, which is
separately provided.
About the engine
1
・The engine is equipped with electronic fuel injection system to correspond to environmental changes
during a long flight.
・This is a four stroke gasoline engine, but runs on a premixed gasoline/2-stroke engine oil.
・Use high quality commercially available 2-stroke engine oil.
・Follow the oil manufacturer's recommedation concerning the mixture ratio of gasoline and oil. In case
of no recommendation by manufacturer, use a 30 : 1 gasoline-to-oil mixture.
・The engine runs counter-clockwise when viewed from the front.
*The specifications are subject to alteration for improvement without notice.
*Consult us for any questions on this product and return for repair.

1
2
3
4
5
6
8
7
9
Rocker cover
Cylinder head
Drive pulley
Drive hub
Propeller washer
Propeller nut
Lock nut
Crankshaft
Driven pulley
Intake manifold
Cylinder
Connector (Injector)
Intake air temperature sensor
Air inlet
Engine bracket
Mounting plate(R)
Mounting plate(F)
Crankcase
Crankshaft rotation sensor
Generator support (R)
OGR-100A Generator
Generator support (F)
10
18
19
20
21
22
16
Names of the parts
22
．
1
．
12
11
13
14
15
17
16
．
17
．
18
．
19
．
20
．
21
．
10
．
2
2
．
3
．
4
．
5
．
6
．
7
．
8
．
9
．
12
．
13
．
14
．
15
．
11
．

Injector
Throttle valve
Injector coupler
Manifold pressure sensor
Throttle servo
Throttle linkage rod
Spark plug (CM-6)
Cylinder head temperature sensor
F-6040 Silencer
Generator mount
Reinforcement beam
Engine mount
32
．
33
．
28
30
31
32
33
34
27
28
．
29
．
30
．
31
．
29
23
24
25
26
Names of the parts
3
23
．
24
．
25
．
26
．
27
．
34
．

Engine control unit (ECU)
ECU connector [CN1]
ECU connector [CN2]
Status display LED
Fuel pump unit
Fuel pressure sensor unit
Pressure release valve
38
．
38
37
34
33
33
．
34
．
35
．
36
．
37
．
Names of the parts
4
39
．
35
36
39

Accessories
5
【Igniter】 Model:IG-08A
・The red connector is a power connector. Supply DC6V～12.6V
(MAX1A) for operation. The ignitor requires a separate power
source from that of the ECU. Install a power switch outsidfe of a
fuselage between Ignitor and power source for safety.
・
Connect the black connector to Ignition signal cable of ECU
【Spark plug】
・Screw into the engine's cylinder head.
・NGK CM-6 Spark plug.
・the hexagon size is 14mm.
・Tightening torque is 12N・m
【Fuel filter】【Non-bubble weight】
・Inline fuel filter to be used between a fuel tank and a pump. The
arrow mark shows the direction of fuel flow.
・Non-bubble weight to be used in a fuel tank to avoid air bubbles
in fuel line.
【Hose clamp】
・To be used to fix pressurized tubes to joints.
・Recommended tube: EIGHTRON Flexible Fluorine (ETFE) Resin
Tubing Clear made by HAKKO CORPORATION / JAPAN
Code No.28382303 FLUORINE(ETFE) RESIN TUBING (2m)
※
Be sure to use this tube where pressure is applied.
【Connector lock】
・For crankshaft rotation sensor，the power connector of Igniter，
and Ignition signal connector to prevent connectors from
disconnecting.
【Socket wrench (SST)】
・A special tool for attaching and detatching the temperature
sensors. (intake air temperature sensor and cylinder head
temperature sensor)
・Attach this tool to 1/4"(6.3mm) Socket wrench handle. (Socket
wrench handle is not included in this set)
【Serial signal converter】
・To be used to convert UART serial signal from ECU to RS-232C
serial signal when ECU is connected to a computer.
【Power supply code】
・Supply power.
・DC10V～17V(MAX1.5A)

6
Accessories
【CAN communication code】
・the connector for CAN communication

■
Cap screw (Hex socket head bolts)
※
Follow the above tightning torque unless otherwise specified.
Standard screw tightening torque
7
M5.0
7.2
screw size
N
・
m
M2.6
1.1
M3.0
1.5
M4.0
3.6

Installation
8
・Drill holes as shown above and bolt the engine to the firewall with standoff mounts and M5 bolts.
・Use standoff mounts with 18mm or more outer diameter made of A2017 aluminum or stronger
material.
・Use 25mm in length standoff mounts to be able to detatch the injector connector, to space the engine
from the fire wall.
・We recommend standoff mounts tobe within 25-30mm length.
Standoff mount
Firewall
Standoff mount

Threaded hole
Unthreaded hole
Unthreaded hole
Threaded hole
Installation
9
・Attach Mounting plate(R) to the Standoff mounts with M5x20 cap screws.
・There are two types of Engine brackets: Engine bracket A and B are different in direction of Engine
support bolts. Choose the proper engine bracker (A or B) to use on the Mounting plate (R) as shown
below.
Engine support bolt
Mounting plate (R)
Mounting plate(R)
Engine bracket
Standoff mount
M5x20 Bolt
Engine bracket A
Engine bracket B
Engine bracket B
Engine bracket A

Installation
10
・Fit the engine to four Engine brackets simultaneously.
・Fasten the four engine support bolts only hand tight at first to align the engine. Then tighten the bolts
with a hex wrench.
・Fasten the engine support bolts next. Do not forget to use Nord-Lock washers otherwise engine
vibration will loosen the bolts and cause a failure.
・Make sure of the Manifold pressure tube is installed as shown below.
Engine support bolt
The tube to measure the manifold pressure
Add the pair of Nord-Lock Washers to the support bolt.
Check this step very carefully. The key faces on inner surface,
and radial teeth on the outer suraface.
Engine support bolt

①
Between the Fuel pump unit and Fuel pressure sensor unit
②
Between the Fuel pressure sensor unit and Injector coupler
Fuel tank
Fuel pump
・
The arrow mark shows the direction of fuel flow.
・
Apply a hose clamp to the pressurized side of the hose.
11
・A one-way valve is built in the fuel pump so pressure remains in the fuel supply line even after stopping
the pump. Open the Pressure release valve to remove residual pressure.
・Use a Non-bubbleweight in the tank to avoid creating air bubbles in the fuel supply tube. Air bubbles
may cause engine misfire and stalling.
・Connect the tubes in the fuel tank firmly to the pipes in a fashion in which they will not easily come off.
Use clamps or wire ties if necessary.
・
Be sure to use [Code No. 28382303 FLUORINE (ETFE) RESIN TUBING (2m)] for piping between the fuel
pump unit and engine(
①
&
②
), through which pressurized fuel passes.
・
Fuel pump unit creates 300kPa pressure. Apply a hose clamp to each hose joint.
・
Connect the Pressure release valve nipple to the Fuel tank with a Return hose.
Installation
・
Connect the Fuel pump unit and the Fuel pressure sensor unit close to the Fuel tank.
・
Use a Fuel filter between Fuel tank and Fuel pump unit
Fuel tank
(not included in this set)
Fuel pump unit
Fuel pressure
sensor unit
pressure sensor
Pressure
release valve
Return hose
Connect to engine
Hose clamp
Fuel filter
Fuel delivery
Connect return hose
Connect fuel pump
Air vent
【Example piping】Teflon rubber tube
Non-bubble weight
Connect fuel tank
Connect
Fuel pressure
sensor unit
Hose clamp

Fuel pressure sensor unit
・Release the residual pressure in the fuel system after a days use to avoid fuel expanding the fuel joints
and causing leaks.
12
Installation
・The Pressure sensor works both from A to B and B to A. Decide the mounting direction according to
your fuselage layout. Apply Hose clamps to both sides of the Pressure sensor.
・To change the direction of Pressure release valve nipple, loosen the Hexagon head with an 8mm
wrench. Tighten the Hexagon head again after deciding the direction.
・If there are air bubbles in the tube between the fuel tank and the fuel pressure sensor unit after filling
up the fuel tank, when the ECU switch is turned on for the first time, open the valve until the screw top
becomes flush with edge of the valve holder as shown below. After eliminating the air bubbles, close the
valve. Do not open the valve more than the flush position to avoid the pressurized fuel from coming out
of the valve.
・Air bubbles beween the Fuel pressure sensor unit and the engine (Injector) are of no concern as they do
no harm since they are discharged through the Injector.
Hexagon head
A
B
Hose clamp Pressure release valve
Valve holder
Pressure release valve (slotted screw)
Do not open past this line.
Valve holder

13
・Connect the tube from the Fuel pressure sensor unit to the Injector joint nipple. Use a Hose clamp. It is
a must.
・Cut off an end of the tube when it is difficult to pull out from a nipple. Do not pull and twist the tube
strongly to pull it out. Do not give damage to a nipple when you use a nipper or a knife to cut the end of
the tube.
Installation
Be sure to use [Code No. 28382303 FLUORINE
(ETFE) RESIN TUBING (2m)] .
・Once a tube is connected to a nipple, an end of the tube is expanded and deformed. Cut the end when
you use the same tube again.
From fuel pressure sensor unit
Hose clamp
Injector coupler
CUT
CUT

・
Mount the Generator after mounting the engine.
Installation
14
・The position of the generator (OGA-100A) is choosable from the three positions shown above.
Right side left side
Lower
M4x30 Bolt
M4x25 Bolt
4.5mm Spacer
15mm Spacer
Use four screw holes for each depending
on the mounting position.
Generator

【
Example when mounting on the left side
】
【
reference
】
Installation
15
1.Remove the pair of front bolts (M4 x 15) on the generator mount, where you intend to fit the
Generator. There bolts are unnecessary in case the Generator is fit.
2. Bolt the Generator support (R) to Mounting plate(F)
together with 15mm Spacers using M4x25 Bolts. Fasten
only temporarily. The Generator support (R) piece has
two sides. Check this closely.
The alignment mark is roughly here when the belt is
new.
7. Fasten the M4x25 bolts of the Generator support (R) that you temporarily fastened earlier. Loosen
the Lock bolt of Generator support (F) and check if belt tension is adjustable by rotating the generator
body.
8. Rotate the generator body clockwise (viewing from the front of the engine) and adust the belt tension.
Press on the middle point of the belt with a finger and set deflection to around 2mm. Tighten the Lock
bolt after adjusting the belt tension.
3. Loosen the Lock bolt on the Generator support(F) and align the
marks as shown above in the red circle. Tension of the belt is the
loosest at this position.
4. Loop the belt over the Drive pulley
and the engine pulley.
5. Insert the Generator into Urethane
bushing of the Generator support (R).
6. Attach the Generator support (F)
to the Generator mount together
with 4.5mm Spacers using M4x30
Bolt.
Generator mount
1. (Please remove it.)
Urethane bushing
2. Generator support(R)
Mounting plate(F)
15mm Spacer
5.
7.
4.5mm Spacer
4.
6.Generator
support(F)
Lock bolt
3. Generator support(F)

[A] Wiring harness A (Sensor and Communication section) {CN1}
A-1
・
Throttle signal input (PWM VIH=2.6V
，
VIL=0.4V
，
MAX5.5V)
・
Fuel trim signal input (PWM VIH=2.6V
，
VIL=0.4V
，
MAX5.5V)
A-2
・
Serial communication (UART
，
TTL logic level is 3.3V)
A-3
・
Fuel pressure sensor
A-4
・
Intake air temperature sensor
・
Cylinder head temperature sensor
・
Manifold air pressure sensor
・
Crankshaft rotation sensor
A-5
・
CAN communication
[B] wiring harness B (Drive section) {CN2}
B-1
・
Power supply (DC10V
～
17V, MAX 1.5A)
B-2
・
Fuel pump
B-3
・
Ignition signal
・
Throttle servo
・
Injector
[C] pump connection cord (extendable)
C-1
・
fuel pressure sensor
・
fuel pump unit
Engine control unit (ECU)
16
[B]
A-1
B-1
A-2
A-3
[A]
[C]
TO FUEL PUMP UNIT
&
FUEL SENSOR UNIT
Connect to engine
B-2
B-3 Connect to engine
A-4
A-5
C-1
ECU

PWM signal
[W
：
Signal
／
B
：
GND] VIH=2.6V
，
VIL=0.4V
，
MAX5.5V
PWM signal
1520μs (neutral) ±420μs
PWM +
→
increase fuel supply The range of increase and decrease is ±30%.
[W
：
Signal
／
B
：
GND] VIH=2.6V
，
VIL=0.4V
，
MAX5.5V
・
the connector for serial communication
UART(TTL logic level is 3.3V.)
[R
：
DC+5V
／
W
：
TX
／
G
：
RX
／
B
：
GND]
Pressure sensor
[R
：
DC+5V
／
W
：
Signal
／
B
：
GND]
PT100 Platinum resistance thermometer
[G
：
No polarity
／
G-W
：
No polarity]
PT100 Platinum resistance thermometer
[Y
：
No polarity
／
Y-W
：
No polarity]
Negative pressure sensor
[R-W
：
DC+5V
／
B
：
Signal
／
B-W
：
GND]
Engine control unit (ECU)
[A]
A-1
・ To be connected to a receiver or throttle signal cable from flight controller.
Specification
Set the travel width so that the PWM signal width is 1100 μs or less on the throttle
closed side and the PWM signal width is 1900 μs or more on the throttle opening
side.
Throttle signal input
A-1
・
In case manual adjustment of fuel injection is necessary, connect to a receiver or
fuel injection signal cable from flight controller.
・
ECU controls quantity of fuel injection normally, so correction signal from the
outside is not necessary. Leave it unconnected or connect 1520μs (neutral) PWM
signal.When pulling out during operation, it holds the state just before.
Specification
Fuel trim signal input
A-2
・To be used to monitor parameters or to connect to a computer for initial setting.
Serial communication
A-3
・To be connected to Fuel pressure sonsor via Pump connection cord.
Specification
Specification
Fuel pressure sensor
A-4
・To be connected to the temperature sensor of the intake port of the throttle valve.
Specification
Intake air temperature sensor
A-4
・ To be connected to the temperature sensor of the cylinder head.
Specification
Cylinder head temperature sensor
Specification
Manifold air pressure sensor
17
A-4
・To be connected to Manifold pressure sensor.
JST
04R
-
JWPF
-
VSLE
-
S

Hall-effect switch.
[BR
：
Signal
／
R
：
DC+5V
／
BR-W
：
GND]
・
the connector for CAN communication
CAN
[R
：
DC+5V
／
W
：
Signal(High)
／
G
：
Signal(Low)
／
B
：
GND]
DC10V
～
17V (MAX 1.5A)
[R
：
Power supply
／
B
：
GND]
[R
：
DC+12V
／
B
：
GND]
[GY
：
Signal
／
R
：
DC+5V
／
B
：
GND]
[W
：
DC+12V
／
G
：
GND (open-drain)]
Engine control unit (ECU)
[A]
A-4
・To be connected to Crankshaft rotation sensor.
Specification
Crankshaft rotation sensor
A-5
Specification
CAN communication
[B]
B-1
Specification
Power supply
・Supply power.
B-2
・To be connected to Fuel pump via Pump connection cord.
Specification
Fuel pump
B-3
・To be connected to Throttle servo.
Specification
Throttle servo
B-3
・To be connected to Injector harness.
Injector
18
Specification
SMP-04C-BC
JST

[BR
：
Signal
／
Y
：
GND]
Extension cord
[R
：
DC+12V
／
B
：
GND]
Extension cord
[R-W
：
DC+5V
／
G
：
Signal
／
B-W
：
GND]
Extension cord (Fuel pump)
[R
：
DC+12V
／
B
：
GND]
Pressure sensor (Fuel pressure sensor)
[R-W
：
DC+5V
／
G
：
Signal
／
B-W
：
GND]
Red
White
Black
Green
Yellow
Gray
Brown
White Stripe
Engine control unit (ECU)
・To be connected to the rotation signal input cable of Igniter.
Specification
Ignition signal
[C]
C-1
[B]
B-3
・To be connected to Fuel pump.
Specification
Fuel pump
Specification
C-1
・To be connected to Fuel pressure sensor.
Fuel pressure sensor
(B-2)
・To be connected to (B-2).
Specification
Fuel pump
(A-3)
・To be connected to (A-3).
Specification
Fuel pressure sensor
Wiring color
R
G
Y
GY
BR
-W
19
W
B