-4-
10. Preparation for engine start (assuming break-in)
(1) Mount the engine on a robust and parallelized test bench or on the fuselage. (Either way, the engine should be fixed and immobile.)
(2) Check whether the throttle valve becomes fully closed and opened certainly.
(3) Check whether each code of the ignition system is connected certainly.
(4) Use 500-600cc tank for the test bench, or a tank which has appropriate capacity for the fuselage.
(5) For piping, only connecting the carburetor with the tank is needed.(Make sure thereʼre no leakage at all the connections.)
(6) For fuel, prepare a mixed gasoline with a volume ratio of “gasoline : oil” = “20 : 1” or richer than that.
(7) Prepare a well balanced 22”x 10” carbon-made prop (Mejzlik is recommended).
*Prop attachment position
Since SAITO 4-stroke gas-engine can be manually started in forward direction of the rotation, fix the prop in the position which facilitates
vigorous cranking.
(8) When starting with an electric starter, also attach a spinner. (This way of start is recommended for safety.)
(9) As it is difficult to judge clearly the peak condition of 4-stroke engines, prepare a tachometer to prevent over-throttling or overheat.
(10) Prepare a fuel pump for gasoline. (Be sure to attach a filter to the intake port. It is available as an option.)
(11) In order to check discharge of the breather, attach a heat-proof and gasoline-proof transparent tube.
(12) Prepare a battery for the electric starter and the bar for carb adjustment & choking (standard accessory).
Caution: If thereʼs anyone stand in front of the engine, be sure to have them move behind the airplane before starting the
engine. Also keep in mind that the exhaust smoke is harmful for health. Keep away one of your arm holding the airplane
away from the prop. Once the engine starts, move behind the airplane. Make needle adjustment or other control from rear. If
the airplane cannot be fixed, ask your assistant to hold the airplane for safety.
Note: Please tighten up the prop regularly at least once in ten flights. Especially for a wooden prop, it tends to compressed so
that the nuts are rather easy to be loosen so please confirm carefully that the nuts are tightened adequately.
11. Method of starting the engine
The following is the procedure with the engine mounted on the airplane. Fill up the tank with fuel.
(Be sure to turn off the switch of the ignition system until just before trying to start up the engine.)
(A) Starting method with a starter (Recommended)
(1) After confirm that the throttle stick is located at the full-close position, turn on the transmitter switch. Then turn on the receiver
switch to check throttle valve and other operation. After that, fully close the throttle valve.
(2) Power on the ignition system.
(3) Open the throttle valve about 1/4 from the full close position by using the throttle stick. (Starting with excessively opened
throttle is dangerous since the airplane jumps forward.)
(4) Apply the starter to the prop and activate for about 5 seconds to start the engine.
(B) Manual starting method (For safety, wear gloves and use a safety stick)
(1) Same as (1) noted above. (The throttle valve must be fully closed. Otherwise, the fuel cannot be manually introduced.)
(2) As shown in Fig.8, pass the choke bar (with M3.5 thread on its tip) thorough the hole in the cowling. Then turn the bar to
insert into the M3.5 internal thread at the center of the throttle lever.
(3) Fully close the throttle and pull the choke bar and fix it with a clip or clamp as shown in Fig.8 so that it may not go back to
the previous position.
(4) Grasp the prop by hand and turn it to the forward direction(CCW) for several times, until the carburetor generates
hissing-like sounds.
(5) After hearing this sound for about 5 times, quickly flick the prop by cranking it some 10 times. Then choking is completed.
(6) Remove the choke bar.
(7) Power on the ignition system and open the throttle valve about 1/4 from the full close position by using the throttle stick.
(Starting with excessively opened throttle is dangerous since the airplane jumps forward.)
(8) Flick the prop quickly and engine will start. If the engine doesnʼt start, repeat the choking procedure (1) to (7).
*After starting, run the engine for 10 to 20 sec to fill up inside the carb with fuel enough before opening the throttle.
12. Break-in
As Break-in is an important procedure to pull out the maximum performance of the engine, it must be cautiously done.
The purpose of break-in is initial lubrication and adjusting of the mobile parts under the condition with rich fuel mixture.
Never make the fuel mixture lean. Lean fuel mixture could cause seizure even during idling or low speed running.
Thereʼs no need to adjust the slow needle at this step as itʼs already set adequately, so you will adjust only the main needle
during break-in.
Procedure;
(1) After filling up the fuel tank, start the engine as described in the above Chapter 11 and run it for 10 sec in low speed.
Fig.8
Choke bar
Temporary
fixed by clip
Throttle lever
M3.5 thread for
Choke bar
Slow needle
Throttle valve
(Move to the left)
Cowling
Standard value for the needles
In case such like follows, reset the needle
to the Standard value (SDV).
・After break-in
・When adjustment canʼt be done correctly.
・When by failure, turning the needle too much.
To set SDV, first fully close the needle.
(DO NOT close too tightly. The needles
can be torn easily).
After that open the needle to SDV as
follows. Throttle valve should be fully
closed during setting to SDV.
SDV for Main needle：
2 turn open from full close
SDV for Slow needle：
4.5 turn open from full close
Throttle lever
Slow needle
CCW
to rich
CW
to lean
Main needle
CCW
to rich
CW
to lean
Fig.9
