OPERATOR'S MANUA
L
SPECIFICATIONS
FIG 2
TAPPET CLEARANCE ADJUSTMENT
1. Tappet clearance is factory preset. No adjustment is necessary unit
after 1 hour of operation (includiing break-in period).
2. Clearance adjustment should be done when the engine is cool.
When the engine temperature is high, clearance is higher due to
thermal expansion.
3. The proper clearance setting should be at 0.04-0.1mm. The adjust-
ment is achieved by loosing the locknut (FIG.2) and turning the
adjusting screw. Tighten the locknut after the adjustment is achieved.
After the initial 1 hour adjustment, this procedure should be performed
after every 2 hours of use.
CAMGEAR TIMIING ADJUSTMENT
If for some reason you have to disassemble your engine, please
follow these important steps on reassembling the cam gear.
1. Remove the carburetor and backplate assembly. Notice the impre-
ssion made on the crankshaft counterweight. Position it directly
straight down or in line with the case outer seam line.
2. When reinstalling the cam gear, the side with a point mark should
be facing the opening of the gear box. Note that it should also be
mounted with the point mark located towards the top of the engine
just below the cam followers.
IMPORTANT!
Silicone rubber is used in many parts of the YS engine.
Use only glow fuel or methanol for cleaning. Gasoline and other volatile
solutions will damage the silicone if used.
WARRANTY
Strict quality control is implemented by our factory in all phases, from
parts manufacturing to final assembly. If performance deteriorates or
a part fails due to a manufacturing error, YS will repair or replace the
engine at no charge in the period of one year from date of purchase.
Warranty does not cover normal maintenance.
Should the engine be modified, incorrectly assembled or abused,
there will be a nomal charge for parts and labor. The use of four cycle
fuel due to the low oil content will also void warranty.
Bore
30.4mm
Stroke
24.8mm
Displacement
18cc
Weight
730g
Practical rpm
2,000-13,000rpm
FIG.1
PROPELLER INSTALLATION
Due to the high torque of the FZ110S engine, we have equipped it
with double locknuts for safety.
1. Mount the propeller and tighten the rear nut. Next, tighten the front
nut as shown in FIG.1.
2. Select a good quality propeller that will turn in the 8,000 to 11,000
rpm range. We recommend sizes 14x11-12, 15x10-11.
START-UP
1. Remove tube(B) from the filter, remove tube(A) from the check
valve, then fill the tank.
Caution: If tank is filled or under pressure remove tube(A) first;
then tube(B). Fuel will eject if tube(B) is removed first while the
tank is pressurized.
2. Open the needle valve 1 1/4~1/2 from the fully closed position.
3. Open the throttle fully and slowly turn the propeller ten turn. This
primes the system by pressurizing the tank and sending fuel to
the carburetor.
4. Pour several drops of fuel into the carburetor.
5. Close the throttle to the idle position and connect the glow plug
cord. The engine is now ready for starting.
Do not attempt to start at full throttle, as this is very dangerous.
BREAK-IN
To maximize engine performance and increase durability, please
follow this break-in procedure:
1. Use the same size (or slightly smaller) propeller than you intend to
use in flying.
2. Use a good quality fuel which contains 15-30% nitromethane and
an oil content of 15-20%. Synthetic or castor oil can be used, or a
combination of synthetic and caster. Do not use four cycle fuel due
to low oil content.
3. The needle valve should be set so that the engine is running at
a rich setting. Run the engine approximately 20 minutes with this
setting.
4. Mount the engine to the model and fly ten times with this setting.
This concludes the break-in procedure. It is advisable to always
use a slightly rich setting to keep the moving parts lubricated,
even after the break-in period.
HIGH SPEED ADJUSTMENT
1. Adjustment of high speed is done by the high speed needle valve.
When it is turned clockwise, the mixture is leaner. When it is turned
counterclockwise, the mixture is richer. A good starting position for
the high speed needle valve is 1 1/4 turns open from fully close
position.
2. When the engine is started, open the throttle gradually. Next, find
the peak position (highest RPM) by adjusting the needle valve.
Then the needle valve should be opened approximately 1/8 of
a turn from full RPM to achieve best performance. The engine may
stop if the throttle is opened to full immediately after starting.
Wait unit the engine temperature rises and then open the throttle
slowly.
3. For flying, it is advisable to use a slightly richer mixture setting. By
using a richer mixture, the engine temperature is maintained and
RPM stability improves.
LOW SPEED ADJUSTMENT
This engine is equipped with a low speed needle valve to adjust
the mixture from low to mid throttle. This needle valve is located on
the side of the throttle barrel opposite the throttle arm ( FIG.1).
1. Open the low speed needle to 3 turns from fully closed position.
2. The low speed needle valve should be set after the high speed
needle valve has been adjusted. Close the throttle gradually to a
idle(approximately 2300rpm). Let it idle for 20 to 30 seconds and
then slowly advance the throttle. The adjustment is satisfactory at
low speed if transition is smooth at this time.
3. If the engine is running rough on idle, the low speed mixture is rich.
If the engine starts to speed up and dies on idle or starts to
detonate, when advancing the throttle, the mixture is lean. Turn
the low speed needle valve clockwise to richen and counterclock-
wise for a leaner mixture (note that the direction of the low speed
needle valve is opposite the high speed needle valve).
Adjustments to the low speed needle valve should be 1/8 to 1/4 of
a turn increment at a time to achieve smooth throttle response.
FEATURES
The FZ110S is the most powerful 110 four cycle engine available.
This engine offers many exclusive features that have been proven on
other YS engines.
Supercharged system with simplified structure to keep weight to a
minimum while still retaining maximum efficiency.
Air chamber that uses crankcase pressure coupled with a double
throttle valve system which allows a bigger charge of fuel and air mix-
ture to enter the intake valve for more power.
Fuel injection system for superior throttle response. This system is
unaffected by tank position or by the attitude of the model.
GlOW PLUG
Select the most appropriate glow plug from those designed specific-
ally for 4 cycle engines. Glow plug selection greatly affects the
miximum engine output and low idle. If RPM's decrease or stop when
the booster cord is removed, replace the plug.
We recommend YS #4 ( YS4GP ) or OS Type F.
INSTALLATION
1
. Connect the engine to the tank as shown in FIG.1. Since high
pressure is applied to the tank, tighten all connections carefully.
Care must be taken to prevent pressure leakage due to undertight-
ening of the check valve or by kinking the fuel lines.
2. Always uses a fuel filter ( not included ). We recommend the YS
filter ( YS1195 ).
3. Match the direction of the check valve arrow to FIG.1, with the
arrow facing towards the tank.
YS FZ110S ( YS0084 )
0.04-0.1mm
Rocker arm
Rock nut
Adjusting screw
Check valve
Fuel filter
Tube (Ｂ）
Tube (Ａ）
Regulator
High speed needle
Low speed needle
Regulator screw
Throttle stop screw
Front nut
Rear nut
