3. Break-in
MOST IMPORTANT!!
●Prop-recommendation : APC-24”x12” for break in.
●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.
●Before starting the engine, open the main needle
Approx. 3 turns
and the slow needle
Approx. 5 turns
CCW
each from full close.
●Start the engine (using a starter is recommended for safety).
●Run for about 5 seconds at low speed to warm up.
●Open throttle gradually up to over half open, in the meantime turn the
main needle CCW. Continue to turn the main needle CCW until the RPM
declines, keeping the throttle opened over half.
●Then
turn the slow needle CCW
to make mixture much richer.
●Run in this very rich condition for 2 tanks.
Note:
●As the fuel contains oil, the exhaust will produce some residue on the airplane.
●Use reliable and well balanced prop, otherwise it can cause abnormal vibration and may result in serious accident.
●During operation, the screws all over the engine can be loosen by heat expansion of metal. Tighten them up
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.
●All responsibilities for the use of the engine, and other obligations and responsibilities based on laws, regula-
tions, 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 the shop or distributor you
purchased from, so that our company will repair them with responsibility. Any failure or trouble caused by
unnecessary disassembly, modification, or other uses than those provided in the instruction manual is not
subject to the warranty.
Φ37.2mm
27.6mm
89.99cc
D24”~25” x P10”xP12”
・Filter with weight [G36-154]
・Durable tube for Gasoline (1m) [G36-155]
・Aluminum spinner nut [57T-30]
・Tappet adjusting kit [120S-161]
・Digital tachometer [G17-167]
Bore
Main body : 3,161g / Muffler : 157g / Ignition : 250g
Stroke
Disp
.
Weight (Approx.）
RPM Range
Approx.
1,300-7,000rpm Max on ground Approx. 6,000-6,500rpm
Propeller
CM-6
Plug
Optional parts
Gasoline 60-70㏄ class
Applications
Battery for ignition system
Voltage:6-12V, greater than 1,000mA
(2-3S Li-Po or 5S NiMH)
・Limit gauge (0.1t) for tappet adjustment 1pc ・Spanner for tappet adjusting lock nut 1pc
・Carburetor adjustment bar 1pc
・Spark plug[CM-6](Attached to the engine) 3pcs ・Muffler set
1set ・Choke bar
1pc
・Ignition system（w/sensor）
1set ・Muffler bracket 1set ・Plug wrench
1pc
・Stand off mount 1set ・Anti-loosening nut
1pc
・Hexagonal wrench
1set
Specifications
FG-90R3 Instruction Manual
4. Needle reference position (Set After Break-in)
●Main needle：Approx.2.5~3 turns from fully close
●Slow needle：Approx.4-1/2~5 turns from fully close（Then throttle should be fully closed）
●Actually the best condition of the needle varies depending on the prop, temperature, humidity and so
on. Please adjust based on the engine performance during flight.
5. 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 cylinders etc.
1.
Remove the spark plug
and rocker arm covers of
#1 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 hexago-
nal 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. Do the same
adjustment for the #3-#2
cylinders in order.
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)
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 (1) Plug cord deeply into the plug of
#1 cylinder to make sure it will not come off. The other
caps and plugs should be installed by the same way.
(Refer to cylinder # on the reverse side)
(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 connector is normally vacant.
For CCW
Make rich
Main
needle
For CW
Open
Throttle
lever
Slow needle
CCW
Rich
CW
Lean
Main needle
Throttle
lever
Standard
accessories
Fuel Tank
Fuel Level
To Outside of the plane
Vent line
fuel supply to carburetor
Fuel filler line
Vent line
Gasoline-compatible
tank stopper
Gasoline-compatible tubing
Filter with weight
Set the center of the carb
slightly above the fuel level
Close as possible
Firewall
Standoff as required
Hollow out referring to
the cutting sheet
Plug Cap
Switch Capacity : 3A〜
Sensor
(2) Sensor cord
Battery
Voltage : 6-12V
Capacity : 1,000mA〜
:
(
1) Plug Cord
Main Unit
(3) Battery Cord
(4) Tachometer Cord
Loosen the lock nut
Adjust the gap turning
the set screw
Top Dead Center
（The state both valves are closed)
Tighten the lock nut
to fix the set screw
3. Method of choke（
No need when you use starter）
●In advance, make a thin hole on the cowling to insert the choke bar /
slow needle adjustment bar.
●During choking, be sure to turn off the switch of the ignition system.
●As shown in the fig, pass the choke bar (with M3.5 thread on its tip)
through the hole on the cowling. Then turn the bar to insert into the
M3.5 internal thread at the center of the throttle lever.
●Fully close the throttle and pull the choke bar and fix it with a clip or
clamp as shown in the fig so that it may not go back to the previous
position.
●Grasp the prop by hand and turn it in the direction of normal operation
(CCW) for several times, until the carburetor generates hissing-like
sound. After hearing this sound for about 5 times, quickly flick the prop
approximately 10 times.
●After that, remove the choke bar. After that, power on the ignition system and flick the prop quickly to start the engine.
If the engine doesnʼt start, repeat the choking procedure.
Cowling
choke bar for insert
M3.5 screw
Throttle lever
Throttle valve
（Move to the left）
Slow needle
choke bar
Temporary fixed
by a clip
1. Fuel
●The fuel is mixture of regular gasoline and high-quality 2-stroke engine oil.
●[Example of oil recommendation]
・ Klotz KL-200 Original Techniplate
・ Deluxe Materials PowerModel 2T-S 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 ratio, is not warranted.
●Do not use gasoline containing ethanol. It may cause not only power loss but also corrosion inside the engine.
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
FG-19R3 Instruction Manual
All specifications and models are subject to change without notice.
