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 Tube (B)

 Tube (A)

 Check Valve

 Fuel Filter

Low Speed Needle Valve

 High Speed NeedleValve

Regulator Adjusting Screw

87

45

97.5

48

35

20

Rear Nut

Front Nut

TAPPET CLEARANCE ADJUSTMENT

1. Tappet clearance is factory preset. No adjustment is necessary until

after 1 hour of operation (including 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 - 0.1mm. The adjustment

is achieved by loosening the locknut (fig.2) and turning the adjusting
screw. Tighten the locknut after the adjustment is achieved. Alter the
initial 1 hour adjustment, this procedure should be performed a few
every 2 hours of use.

CAM GEAR TIMING 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 impression

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.

DIAPHRAGM AND CHECK VALVE DISASSEMBLY

Diaphragm
1. Remove the adjustment screw of the valve, and then remove the inside

valve and spring.

2. Clean the inside with alcohol or appropriate cleaner. Reassemble.
3. Screw in the regulator screw until flush with the diaphragm body.

Check valve
1. Open the valve by rotating the body counterclockwise.
2. Reassemble the check valve carefully.

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.

                 

SPECIFICATIONS

Bore

26.2mm

Stroke

19.0mm

Weight (engine)

460g

(muffler)

33g

Practical rpm

2,000-15,000rpm

OPERATORS MANUAL

Fig.1

FEATURES

 The New FZ63S has set the standard by which all other 4 stroke engines
in this size category are judged.
• New regulator design for more reliable operation in high temperature
  conditions.
• New cylinder desighn provides higher power and improves cooling for
  longer life.
• New crankcase design is stronger to resist distortion under high horse
  power loads

GLOW PLUG

Select the most appropriate plug from those designed specifically for

4 cycle engines. Glow  plug selection greatly affects the maximum
engine output and low idle. We recommend the  YS  #4.

INSTALLATION

l.

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 under tightening of the check
valve or by kinking the fuel lines.

2. Always use a fuel filter. We recommend the YS fuel filter.

3. Match the direction of the check valve arrow fig.1 with the arrow facing

to wards the tank.

PROPELLER INSTALLATION

Due to the high torque of the FZ63 engine, we have equipped it with

a double lock system 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 9,000 to 12,000

rpm range. We recommend sizes 11x7-11x9,12x6-12x8.

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 while the
tank is pressurized. )

2. Open the needle valve 2  l/2 turns from the fully closed position.

3. Open the throttle fully and slowly turn the propeller 10 times. This

primes the system by pressurizing the tank and sending fuel to the
carburetor.

4. Close the throttle to the idle position and connect the glow  plug battery.

The engine is now ready for starting.

DO  NOT  ATTEMPT  TO  START  FULL  THROTTLE,
AS  THIS  IS  VERY DANGEROUS.

,

BREAK IN

To maximize engine performance and increase durability, please follow
this break-in procedure:

l.

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 oil

content of 20-24%. Synthetic or castor oil can be used, or a combination
of synthetic and castor.
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 carburetor needle valve.When

the needle valve 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 2 1/2 turns open from the fully
closed 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 until 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 new 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 1 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 2500rpm). 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 counterclockwise 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.

IMPORTANT!  The regulator adjusting screw on this engine is
factory set. No further adjustments are necessary. If for some reason
you have to disassemble the regulator assembly, the regulator
adjusting screw should be set flush with the regulator body.

Fig.2

0 - 0.1mm

FZ63S

 (Part No. YS0064)

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