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2.

  Close the throttle slowly and adjust 

the low speed setting by rotating the 

idle needle valve (89) clockwise to lean 

the mixture and counterclockwise to 

richen the mixture.

Note:

  The fuel mixture is too rich 

if, when opening the throttle rapidly, 

the engine emits white smoke and 

“stutters” or “stumbles.” Correct 

this by rotating the idle needle valve 

clockwise 1/4 to 1/2 turn at a time  

until the engine transitions smoothly 

without hesitation upon opening the 

throttle rapidly.

The fuel mixture may be too lean if the 

engine stops at the lowest idle position, 

or when the throttle is rapidly opened 

from idle. Attempt to correct this by 

rotating the idle needle valve counter- 

clockwise 1/4 to 1/2 turn at a time until 

the engine transitions smoothly without 

hesitation upon opening the throttle 

rapidly. If the situation is not rectified 

by counterclockwise rotations of the 

idle needle valve, turn the idle  

needle valve clockwise in 1/4 to 1/2  

turn increments.

3.

  After obtaining the proper idle 

setting, the low rpm setting may be 

made through the positioning of the  

throttle adjustment screw, if applicable. 

If not, adjust the idle setting via the 

throttle trim of your transmitter.

Normal Engine 

Operation

If break-in was accomplished on a test 

bench, your engine may be mounted to 

the aircraft and flown. The initial flight 

should be performed with the engine 

adjusted for a rich fuel mixture.

1.

  Your Saito

 engine should be 

securely mounted to the aircraft. There 

are many motor mounts available; 

however, a high-quality metal mount, 

such as those manufactured by Saito 

exclusively for Saito engines, is 

considered to be the best. 

2.

  General operating procedures that 

will ensure long engine life are:

•  Do not operate the engine with a 

“lean” mixture.

•  Regularly check all screws and nuts 

on both the engine and muffler.

•  After 1 to 2 hours of operation, valve 

adjustment may be necessary. Adjust 

the valves as shown in the “Engine 

Maintenance” section.

•  The Saito engines are equipped 

with a breather nipple (19). It is 

recommended that a length of 

silicone tubing be attached to this 

crankcase breather nipple (19) 

and routed away from the engine 

compartment so the excess oil can be 

expelled outside of the aircraft.

C A R B U R E T O R   A D J U S T M E N T S

 7

•  Connect the heating source to the 

glow plug.

•  Using either the “Start Stick 

(HAN113)” or electric starter, spin 

the propeller until the engine is 

running.

Note:  A very common error is to 

remove the glow plug igniter too early. 

It is suggested that the igniter be left 

attached until after the engine has been 

run up and the high-speed needle valve 

has been properly adjusted.

8.  Initial break-in:  

Do not exceed 4,000 rpm for the first 

10 minutes of operation. This allows 

all parts to mate properly with good 

lubrication. 

Note:  Due to the excessively “rich” 

mixture setting, it may be necessary to 

leave the heat source attached to the 

glow plug.

Subsequent runs may be made while 

slightly leaning out the mixture with 

each tank full of fuel. Forty minutes is 

considered sufficient time for normal 

break-in prior to the first flight.

9.  After break-in:

If a test stand was used for the break-

in procedure, the engine may now be 

mounted in the aircraft using a high-

quality motor mount such as those 

available from Saito

 specifically or 

for Saito engines.

The idle needle valve (89) may now be 

refined. Please refer to the “Carburetor 

Adjustments” section shown below for 

information on how to do so.

The valves may also be checked 

at this time. Refer to the “Engine 

Maintenance” section on page 8–9 

for information on the valve/tappet 

adjustments.

The use of a tachometer is encouraged 

for setting the high-speed needle valve 

(85) prior to flight. The peak rpm 

should be obtained and then reduced 

by approximately 200 – 300 rpm by 

turning the high-speed needle valve 

counter-clockwise (richen). Each 

engine’s peak rpm can be found on the 

“Propeller Chart” on page 14. Over-

revving of a 4-stroke engine can cause 

internal damage to the engine.

Carburetor 

Adjustments for Two- 

Needle Carburetors

The low-speed, or idle needle valve 

(89), is preadjusted at the factory for 

best performance during break-in. 

After break-in it may be necessary to 

“fine tune” the low speed adjustment 

using the following procedure:

1.

  Start the engine and let it warm up 

prior to attempting any adjustments.

S T A R T I N G   T H E   E N G I N E

Summary of Contents for FA-120 Special

Page 1: ...INSTRUCTION MANUAL Large Single Cylinder 4 Stroke Engines Version 2005 FA 120 Special FA 120S Golden Knight FA 150 FA 150 Golden Knight FA 180 FA 180 Golden Knight FA 220a FA 220a Golden Knight...

Page 2: ...ller for your engine refer to the Propeller Chart on page 14 of this manual 4 It is extremely important to balance the propeller prior to installation of the engine Failure to do so may cause damage t...

Page 3: ...ety of electric starters on the market The Hangar 9 PowerPro Heavy Duty 12V starter HAN162 will work perfectly on all Saito engines 6 Tachometer The use of a tachometer for setting the high speed need...

Page 4: ...Close throttle to 1 4 1 3 open position Rotate propeller clockwise until it is against the compression stroke S T A R T I N G T H E E N G I N E 5 Break In The first run on any engine whether 2 cycle o...

Page 5: ...his crankcase breather nipple 19 and routed away from the engine compartment so the excess oil can be expelled outside of the aircraft C A R B U R E T O R A D J U S T M E N T S 7 Connect the heating s...

Page 6: ...s pattern 2 Assemble the cam gear lining up the timing mark at the 6 o clock position The crankshaft must be positioned at the 12 o clock or top dead center TDC position refer to Figure 1 below 3 Reas...

Page 7: ...uel Pump System When operating the FA 220a GK engine with a remote fuel tank it may be necessary to use the optional fuel pump system SAI220a102 The fuel pump system provides additional pressure to th...

Page 8: ...1C 150S821C 180821B 180821B 180821B 180821B 822 Carburetor Complete Right 831 Carburetor Body Assembly Left 120S831B 120S831B 150S831A 150S831A 180831 180831 180831 180831 84 Spray Bar Assembly 450R3D...

Page 9: ...nstallation onto your Saito engine Failure to do so may cause unwanted vibration in your aircraft Figure 5 Saito Single Cylinder Propeller Chart NOTE All recommendations are based on engines using APC...

Page 10: ...clude a phone number where you can be reached during the business day If your engine needs repair please do the following Consumer Warranty and Repair Policy 31 33 36 38 37 32 27 06 07 24 09 46 14 32...

Page 11: ...t Address _______________________________________________________________________ City State Zip _______________________________________________________________________ Please cut on dotted line 18 W...

Page 12: ...Distributed exclusively by Horizon Hobby Inc Champaign IL 61822 www horizonhobby com 2005 SAIMAN1L 7658...

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