Φ32.0mm
26.0mm
20.9cc
15”x8“~16”x6”
・Filter with weight [G36-154]
・Durable tube for Gasoline (1m) [G36-155]
・Aluminum spinner nut [100-30]
・Tappet adjusting kit [30-161]
・Digital tachometer [G17-167]
Bore
Body: 690g / Muffler: 83g / Ignition system: 100g / Engine mount: 156g
Stroke
Disp
.
Weight (Approx.）
RPM Range
Approx. 2,000-9,500rpm
Max on ground Approx. 8,000-9,000rpm
Propeller
SP-1 or SP-2
Plug
Optional parts
4-stroke glow 100-110 class
Applications
Battery for ignition system
Specifications
FG-21 Instruction Manual
2. Ignition
●Ignition arrangement- Place the main unit as far from other
electrical devices as possible.
(1) Plug cord（meshed high tension cord)
Insert the plug cap of the plug cord deeply into the plug
attached to the cylinder to make sure it will not come off.
(2) Sensor cord
Connect with the cord from the sensor attached to the engine.
(3) Battery cord (black / red cord)
Use a fully charged battery that has adequate spec. (6-12V, more
than 1000mA is recommended). Between the battery and main
unit, make sure to set a heavy duty switch whose capacity is
higher than 3A.
(4)Tachometer cord
Connect the digital tachometer (Option). Otherwise the connec-
tor is normally vacant.
※
Standard
accessories
6. Tappet adjustment
The valve clearance should be checked and adjusted after Break-in and every after 2 hours while the engine is cold. Before adjusting
tappet gaps, tighten the screws around cylinder etc.
1. Remove the spark plug and
rocker arm covers from the
cylinder. Then turn the prop
CCW by hand to place the
piston at TDC of compression
stroke.
2. Loosen the lock nut and
adjust the gap by hexagonal
wrench until you get the
correct gap (below pic) for
both of intake & exhaust.
3. Once the gap is set, tighten
the lock nut and attach the
plug and covers.
4. Turn the prop by hand to
check if the compression is
enough. If the gap is less than
0, the valve is always opened
sightly and lose compression.
Then adjust again.
Correct Gap
Must not be inserted
Close to “0” with no limit
Limit gauge
(0.1mm)
Loosen the lock nut
Adjust the gap turning
the set screw
Top Dead Center
（both valves are closed)
Tighten the lock nut
to fix the set screw
・
Engine mount set
1set
・Limit gauge (0.1t) for tappet adjustment
1pc
・Plug wrench
1pc
・Hexagonal wrench
1set
・Spanner for tappet adjusting lock nut
1pc
・Muffler set
1set
・Ignition system(w/sensor) 1set
・Spark plug[SP-2](Attached to the engine)
1pc
・Anti-loosening nut
1pc
Switch Capacity : 3A〜
Sensor
Battery
Voltage : 6-12V
Capacity : 1,000mA〜
:
Plug cap
(2)Sensor cord
(Black)
(1)Plug cord
Main unit
(3)Battery Cord
(Red/Black)
(4)Tachometer cord
(Brown/Red/Orange)
Fuel Tank
Fuel Level
To Outside of the plane
Vent line
fuel supply to carburetor
Set the center of the carb
slightly above the fuel level
Fuel filler line
Vent line
Gasoline-compatible
tank stopper
Gasoline-compatible tubing
Filter with weight
Close as possible (within 200mm)
Fire wall
CCW to make
rich
Main
Needle
Throttle
Full open
SAITO SEISAKUSHO, CO., LTD.
www.saito-mfg.com
22-7, 3-chome, Tokagi, Ichikawa-shi, Chiba prefecture 272-0024, Japan Phone: 047-378-4156 FAX: 047-378-4155
All specifications and models are subject to change without notice.
Note:
●As it uses oil-mixed fuel, the plane may sometimes get dirty from the exhaust.
●Use a reliable and well-balanced prop. Otherwise it may cause an abnormal vibration and could result in a serious accident.
●During operation, all engine screws can loosen due to metal heat expansion. Check and tighten occasionally.
●When the exhaust valve gets dull by carbon or sludge especially in cold atmosphere, remove the rocker cover and apply some anti-rust
spray to the exhaust valve to help the valve to move smoothly.
●Pay attention to the surroundings so as not to disturb others by noise and exhaust.
●Always keep spectators stand behind the engine when operating the engine.
●As exhaust smoke is harmful, be careful not to breathe in or otherwise expose yourself to its harmful effects.
●Pay attention not to touch the rotating propeller when starting engine, and move to rear side of the aircraft once the engine is started.
●All responsibilities for the use of the engine, and other obligations and responsibilities based on laws, regulations, etc. are borne by the
purchaser and the user, and SAITO SEISAKUSHO CO., LTD. is exempt from any responsibilities.
Warranty:
●If there is any deficiency from the factory concerning manufacture, please consult with the shop or distributor you bought from. Our
company will be responsible for repair. However, any failure or trouble caused by unnecessary disassembly, modification, or other uses
than those provided in the instruction manual is not subject to warranty.
●Ignition system is subject to the warranty only for initial failure. Once the system has been activated successfully, it will no longer be subject
to warranty.
ver. March, 2022
1. Fuel
●The fuel is mixture of regular gasoline or high-octane gasoline and high-quality 2-stroke engine oil.
●[Example of oil recommendation]
・ Klotz KL-200 Original Techniplate ・ Deluxe Materials PowerModel 2T-S ・ ENEOS RACING SPEC PRO-2T (SAITO STANDARD) etc.
If such oils are not available in your country, then please ask the official SAITO distributor in your country for an alternative.
NEVER use “cheap oil” designed for utility engines
for brush cutter, lawn mower, or chain saw etc.
●Be sure to use the mixture “gasoline : oil =15~20 : 1” by volume ratio. (Ex. 1000ml of gasoline should be mixed with more than 50ml of oil ).
●During the break-in process,
use 15:1 mixed fuel
to ensure the best lubrication for initial running.
●Any damage caused by the fuel used, in which the oil ratio is lower than 20:1 will not be covered by warranty.
●Do not use gasoline containing ethanol. It may cause not only power loss but also corrosion inside the engine.
3. Propeller
●Recommended propeller is APC15x8~16x6 which brings approx.9,000rpm. Larger size or greater pitch can cause engine broken due to
overload.
●Use a well-balanced one. Never use the propeller that has been scratched or damaged even if slightly.
●As the propeller is compressed slightly, tighten the propeller nut every hour of operation.
4. Break-in
MOST IMPORTANT!!
●Prop-recommendation : APC16”x 6”.
●Use 15:1 fuel:oil ratio for break-in.
●Never make the fuel mixture lean during break-in. It could cause seizure even during idling or
low-speed running.
●Check that the slow needle is set to the reference position. (Depth 0.9~1.1mm from the surface of
the throttle lever. )
●Before starting the engine, open the main needle Approx. 1+1/2 turns from fully closed.
●Start the engine (using a starter is recommended for safety).
●Soon after starting, Open throttle gradually up to full. In the meantime turn the main needle CCW.
Continue to turn the main needle CCW until the RPM declines (to approx 4-5,000rpm) keeping
the throttle opened fully.
●Run in this very rich condition for 1 liter of fuel.
●Now “initial” break-in is done.
Slow
High
Throttle lever
CCW→Rich
CC→Lean
Main needle
Slow (Idle) Needle
(Adjust with ⊖ screw driver)
CW→Lean
CCW→Rich
Approx.
0.9~1.1mm
Slow Needle
5. Adjustment of carburetor after initial break-in.
◇Needle reference position (Set after initial break-in)
●Start the engine after adjusting the needle to the following reference value.
●Main needle：Approx. 1+1/3~1+1/2 turns CCW from fully closed
●Slow needle：Approx. 2+1/2~3 turns CW (Approx. 0.9~1.1mm) from the surface of the throttle lever. (Then throttle valve should be fully
closed)
●Actually, the best position of the needles vary depending on the prop,
temperature, humidity and so on. Please adjust as necessary after
observing the engine performance during flight.
◇Peak adjustment
●After starting the engine, warm up for approx. 30 seconds at low speed.
●Achieve the peak at full throttle.
→Turn the main needle CW gradually to the position where the RPM is
greatest (the peak). Continuing to turn the needle CW past the peak
could lead to seizure so turn it slowly and carefully. If the RPM sudden-
ly decreases after passing the peak,
instantly return the main needle
CCW
to again increase the RPM. Otherwise it could damage the engine
seriously.
●Once achieving peak RPM, return the throttle to low speed. Make a note of the position of main needle at the peak at that time. ( How many
turns you did CW based on the reference value. )
◇
Slow needle Adjustment
●
After achieving peak RPM, next is slow needle adjustment. Open the throttle from low RPM to full throttle quickly.
●Turn the slow needle CCW slightly if the engine hesitates for a moment or stalls before the engine reaches max RPM because the mixture is
too lean.
●Turn the slow needle CW slightly if the engine is slow to reach peak RPM (full throttle set) because the mixture is too rich.
●Adjust the slow needle as above until the RPM follows the throttle movement smoothly. The important point is to adjust the slow needle
AFTER
the main needle has been adjusted to its peak.
●Now break-in at ground level is done. Adjust tappets by the method described later.
◇Pre-flight / Flight adjustment
●When the slow needle adjustment is done, check the response by revving up from low speed to full throttle quickly several times.
●Open the throttle fully and turn the main needle CCW approx. 60〜90 degrees from the peak position. This is to make the fuel mixture richer
in the air where the RPM get higher than on the ground.
●After all adjustments are made, fly your aircraft and fine tune the engine according to the situation. Basically tuning should be done with the
main needle. Readjustment of the slow needle is rarely needed if the first adjustment of the slow needle has been done successfully.
Voltage:6-12V, greater than 1,000mA
※If you use Li-Po, we recommend the spec less than 2,500mA capacity and
less than 30C discharge rate
