User Manual
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7. Carburetor
A carburetor with a pump developed exclusively for our small-size four cycle gasoline engine is mounted, instead of using
muffler pressure.
Since the carburetor with a pump introduces the air from the air hole, cut out the hole on the firewall as adequate size.
When adjust the carburetor, refer to Fig.7
Main needle: To adjust the speed at the time of full open of the throttle valve.
Slow needle: To adjust the speed from the idling to the middle speed.
Turning each needle in clockwise direction, the fuel will become leaner and the rotation speed will increase. Turning it in
counterclockwise direction, the fuel will become richer and the rotation speed will decrease.
Standard value for the needles
For Main needle：
1+1/41+1/2 turn open
from full close
For Slow needle：
Approx. 8 turn open from
full close
(Then throttle valve should be
fully closed)
Actually the best condition of the
needles varies depending on the
prop, temperature, humidity and
so on.
Please adjust seeing the engine
performance during flight.
Slow （Idle) Needle
(Adjust with ⊖screw driver)
CW→Lean
CCW→Rich
CW→Lean
CCW→Rich
Main Needle
CW→Lean
CCW→Rich
Slow
High
Throttle lever
5. Ignition system
*Be careful of possibility of electrical shock as it generates high voltage.
*The unit includes a plastic clip to hold the connectors and spiral tube to protect each wire.
The ignition system is designed to match SAITO 4-stroke gas-engines with automatic advancing system.
However this ignition system is designed to be an anti-noise product, please isolate it completely from the receiver, servo, and
battery to avoid a radio-interference trouble. Moreover, it is desirable to utilize a noise filter (line filter). Especially, each switch
(for Ignition and for Receiver) should be isolated and set far from each ones.
Caution: A gas-engine generates a noise which has an adverse effect on RC adjustment. Please be sure to carry out a noise
check each time while the engine is running before flight. Since a noise which occurs during flight may lead to a large-scale
accident, please carry out a noise check without fail. As a simple method, after starting engine you can check by removing
the antenna of the transmitter and operate it about 50m away from the airplane. If there is no malfunction, it is normal.
The function of each cord;
(1) Plug cord (meshed high tension cord)
As Fig.6 shows there are three cords available for three cylinders. Make sure to attach each number described on the main
unit to the cylinder. (Refer to Fig.2 regarding cylinder number). When you put on the plug cap, insert deep into the plug to
avoid coming off during flight. And then pull the plug cap to confirm that it wont come off.
(2) Sensor cord (Gray cord with exclusive connector)
Connect with the cord from the sensor attached to the engine.
(3) Battery cord (black/red cord)
Please use the fully charged battery that has adequate spec. (6-9V, more than 1000mA is recommended.). Between the
battery and main unit, make sure to set an ignition switch whose capacity is higher than 3A.
(4)Tachometer cord (black/red/white cord)
Connect the digital tachometer (Option). Otherwise the connector is normally vacant.
6. Spark plug
SAITO SP-1 spark plug is the standard
equipment.
Dimensions are as follows;
Hexagon width: 8mm
Screw size : UNEF1/4-32mm
Reach : 5.5mm
Spark-gap : 0.4-0.5mm
For replacement, please replace with SAITO
SP-1.
Since SAITO 4-stroke engine uses mixed
gasoline, please decide the numbers of
flights by yourself to clean the spark plug.
Please replace, when it is degraded.
(Consider the plug as consumable.)
Plug cap
Switch (not included)
Capacity: more than 3A
Sensor
(2)Sensor cord
(1)Plug cord
Main unit
(3)Battery cord
(4)Tachometer cord
Recommended battery
5cell-NiMH or 2cell-LiPo
Voltage:6-8.4V
Capacity: 1,000mA
Fig.6
Fig.7
Note: The carburetor for the gasoline engine is the assembly of very strict and delicate parts. So please make sure to use filtered
gasoline. Moreover, DO NOT disassemble by yourself. If therere any troubles regarding carb, please consult the shop from which
you bought the engine.