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26

When the engine is started, make sure the radio control 
system works normally (distance test).

Engine does not run erratic with full throttle.

Idling is stable.

Responds positively to the throttle operation.

Warm-up is finished.

FLIGHT & MAINTENANCE

Checking prior to flight

Warm-up is required as with full size aircraft and car engines. 
Take  off  the  model  after  warming  the  engine  for  approx.  10 
seconds with full throttle.

Precautions in flight

A  slight  engine  rpm  increase  and  decrease  delay  is 
normal. Abrupt throttle operation will the cause engine to 
quit. Move throttle smoothly. 

Due  to  the  construction  of  the  carburetor,  70~80%  of 
maximum power develops with half throttle.
If  you  feel  uneasy  with  this,  adjust  with  transmitter 
function  (exponential  and  throttle  curve,  etc.)  or 
differential of throttle linkage.

Maintenance after the day’s flights

Please  pay  attention  to  the  matter  described  below  to 
ensure  that  your  engine  serves  you  well  in  regard  to 
performance, reliability and long life.

Check  the  tightening  of  each  screw,  especially  engine 
installing  screws  and  silencer  installing  screws  each 
time.  Also, for the first several flights, tighten the screws 
after each flight.

Cooling  is  more  vitally  important  to  a  gasoline  engine 
than to a glow engine. If overheating symptoms (loss of 
power  at  full  throttle  or  exhaust  note  at  mid  speed 
changes  from  cloudy  one  to  clear  one)  are  observed 
during  flight,  immediately  stop  flying  and  carry  out  the 
following countermeasures.

Enlarge the air intake cutout on the cowling.
Enlarge  the  air  outlet  cutout  on  the  cowling.  (It  is 
vitally important.)
Partly cover the air intake cutout on the cowling where 
air does not hit direct the engine.
Install an air guiding plate on the fuselage and cowling 
so  that  cooling  air  may  be  guided  to  the  cylinder 
portion of the engine and muffler.

When  the  interval  between  the  flights  is  short  and  the 
engine  is  still  hot,  it  may  be  possible  overheating 
symptoms are observed by circulating the head from the 
former flight through the engine even if the overheating 
symptoms were not observed during the former flight. In 
this case, leave it until the engine is fully cooled down (in 
hot weather, it may take more than one hour.) or run the 
engine for 4 to 5 minutes at idling.

1) 

2) 

3) 

4) 

27

Fill the carburetor with fuel at the conclusion of a day's 
flying.  (Pay  careful  attention  to  fire  and  ignition  source 
when carrying and storing the model.) 
If the engine is stored without filling the carburetor, with 
fuel the inside parts will dry out and not work properly at 
the next running. If the engine quits out of fuel, refill the 
carburetor with fuel.

When  the  engine  is  not  to  be  used  for  a  long  period 
(more than a year), remove the engine from the model, 
clean the outside then remove the carburetor, and plug 
all  tubing.  Clean  inside  the  engine  by  rotating  the 
crankshaft  with  the  engine  immersed  in  container  filled 
with gasoline.

Also use gasoline to clean the outside of the carburetor. 
Do  not  use  kerosene,  or  the  inside  parts  will  be 
damaged.  Clean  the  outside  only  because  the  inside 
parts are sensitive to foreign matter.

After cleaning the engine, dry it well then inject a small 
quantity of oil used to mix fuel and rotate the crankshaft 
several times to distribute the oil well inside the engine.  
Finally reassemble the engine and store it in a dry place 
after inserting it in a heavy vinyl bag.

As  previously  mentioned,  it  is  vitally  important  to  avoid 
operating  the  engine  in  conditions  where  dust, 
distributed  by  the  propeller,  may  be  deposited  on  the 
engine and enter its working parts.

Remember to keep your fuel container closed to prevent 
foreign matter from contaminating the fuel.

Install  a  fuel  filter  to  prevent  foreign  matter  in  the  fuel 
container  from  entering  the  fuel  tank.  O.S.  Super  Filter 
(L) is available as an optional extra.

Install  an  in-line  fuel  filter  between  the  tank  and 
carburetor  to  prevent  foreign  matter  in  the  tank  from 
entering the carburetor.

Clean these filters periodically.

If  these  precautions  are  neglected,  restrictions  of  fuel 
flow  may  cause  the  engine  to  cut  out,  or  the  fuel/air 
mixture  to  become  too  lean  causing  the  engine  to 
overheat.

With  a  gasoline  engine  rust  hardly  occurs.  Check  the 
exterior  to  make  sure  there  is  nothing  wrong  and  wipe 
off any oil res.

Summary of Contents for GT55

Page 1: ...ou may readily refer to them whenever necessary It is suggested that any instructions supplied with the aircraft radio control equipment etc are accessible for checking at the same time Two stroke gasoline engine for airplanes 1 SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O S ENGINE ABOUT THE ENGINE ENGINE PARTS NAME SILENCER INSTALLATION FUEL TANK LINES CARBURETOR WLA 2 PARTS NAME CARBURETOR LINK...

Page 2: ...lse to smoke near to it Carry out the mixing of the gasoline and oil outdoors or in a well ventilated place away from any source of fire to prevent the possibility of a fire Refill the fuel tank only after the engine is well cooled down or there is a danger of fire 3 WARNINGS Model engines generates considerable heat Do not touch any part of your engine until it has cooled Contact with the muffler...

Page 3: ... loose objects such as pencils screwdrivers etc in a shirt pocket from where they could fall through the propeller arc Use an electric starter for this engine The wearing of safety glasses is also strongly recommended If you try hand starting be sure to use a chicken stick or heavy glove Never attempt to start the engine with a bare hand Be sure to carry out adjustments of the high speed needle an...

Page 4: ...attery voltage drops It provide high voltage for sure firing through the operating range while utilizing a low current draw STANDARD ACCESSORIES Spark Plug CM 6 入力電圧 消費電流 出力電圧 Input voltage Consumption current Output voltage DC 4 8V 7 6V 600mA 6000rpm 4 8V 20KV 6000rpm 4 8V Exhaust Gasket GT55 Ignition module Assembly IG 01 7 Propeller Retaining Screws ENGINE PARTS NAME Spark Plug Cylinder Head Cr...

Page 5: ...ngine cooling to avoid overheating Pay careful attention to the cooling since a gasoline engine generates more heat than a glow engine Secure at least a 30mm dia area around the air intake of the velocity stack so that the air intake will not be restricted Cut out the cowling big enough if necessary 9 Use a tank designed for gasoline Tanks designed for glow fuel use a rubber cap which is deteriora...

Page 6: ... retaining screw Pay attention not to lose this screw because it is special size At this time be careful not to remove the high speed stop lever Then install the throttle lever with the throttle lever retaining screw Then install the idle speed stop lever with the high speed stop lever retaining screw Connect the throttle linkage so that the engine can be stopped via radio operation Connect the th...

Page 7: ...t tubing to the inside of the fuselage 13 Consumption current is 600mA 6 000rpm User a power source of more than 1000mA h capacity For safety with this ignition module the engine runs intermittently over 5 000rpm when the power source voltage drops below 3 8V With this intermittent running rpm do not increase the rpm above mid speed and land the model immediately The ignition module is set not to ...

Page 8: ...e possibility of flying apart due to strong centrifugal force caused by high rpm Discard any propeller which has become split cracked nicked or otherwise rendered unsafe Never attempt to repair such a propeller destroy it Do not modify a propeller in any way PROPELLER Use a wooden or a carbon fiber propeller Do not use a nylon propeller The choice of propeller depends on the design and weight of t...

Page 9: ...l If there is no recommendation mix with a 30 1 ratio We have checked and approved the following oil mixture ratio KLOTZ ModelLube 50 1 COSMO Cosmo Terra 2 cycle 50 1 RED LINE Two Stroke Racing Oil 40 1 This does not mean we guarantee the quality of these oils Follow the instructions in the running in section concerning the mixture for running in With a gasoline engine passages in the carburetor a...

Page 10: ...g loose gravel or sand The propeller may throw such material in your face and eyes and cause injury WARNING When ground running the engine avoid dusty or sandy locations If dust or grit is drawn into the engine this can have a ruinous effect drastically shortening engine life in a matter of minutes 19 1 2 3 4 5 6 7 8 9 When starting the engine for the first time set both the high speed needle and ...

Page 11: ...on the transmitter 1 2 3 21 1 2 3 4 5 4 5 6 7 8 9 1 2 3 Make sure the ignition switch is off Close the choke valve fully Fully advance the throttle stick on the transmitter Flip a propeller 2 3 times 3 4 times in winter In case of upright and side installation flip 3 4 times Open the choke valve fully Flip the propeller 6 7 times to draw the mixture into the cylinder with the throttle stick fully ...

Page 12: ...at the procedure over priming is suspected Check whether the plug is wet or not If the plug is wet replace it or wait until it is dried Then flip the propeller swiftly 15 20 times with the plug removed to eject the fuel in the cylinder Then install the plug and repeat the starting procedure 23 1 2 4 5 6 7 8 3 Set the throttle stick at bottom or 1 8 2 3 clicks advanced from the bottom Make sure the...

Page 13: ...gine does not respond sluggishly to increase rpm nor hesitates before picking up speed or even ceases firing If the engine responds sluggishly to increase rpm the mixture is too rich due to the slow speed needle being open too far Close the slow speed needle approx 15 degrees Repeat this procedure until the engine accelerates smoothly Be sure to adjust the slow speed needle only after stopping the...

Page 14: ...erheating symptoms were not observed during the former flight In this case leave it until the engine is fully cooled down in hot weather it may take more than one hour or run the engine for 4 to 5 minutes at idling 1 2 3 4 27 Fill the carburetor with fuel at the conclusion of a day s flying Pay careful attention to fire and ignition source when carrying and storing the model If the engine is store...

Page 15: ...3 4 5 6 7 8 9 10 11 12 12 1 13 14 15 15 1 15 2 16 17 18 18 1 19 20 21 22 29704000 29714100 29703100 29703400 29703200 29706000 29717000 29705000 29781300 29781000 29781110 29781500 29701200 29701210 29709000 29702100 29708000 29708100 29708200 29730000 29701000 29701300 29701310 29731000 29702000 29714200 29707000 74002000 74002200 71669000 29714300 Description Code No No Cylinder Head Head Gasket...

Page 16: ... Plug Friction Screw Idle Speed Needle High Speed Spring Needle H ADJ Needle Idle Spring Needle ADJ Choke Arm Assy N4 40x5 Retaining Screw Shaft Choke Valve Choke 4 40x4 Retaining Screw Lever Outer Shaft Throttle Ring Retaining Valve Throttle Spring Throttle Return Link Throttle Throttle Arm Assy N4 40x5 Retaining Screw 20 21 22 23 24 24 1 24 2 24 3 24 4 24 5 24 6 25 26 27 28 29781020 29781030 297...

Page 17: ...r M5 Stand Off Engine Mount 1 1 4 31 8mm 4pcs Hex Socket Head Bolt M5x15 10pcs sets Hex Socket Head Bolt M5x25 10pcs sets Lock Washer M5 10sets Propeller Washer M5 Stand Off Engine Mount 1 1 2 38 1mm 4pcs Hex Socket Head Bolt M5x15 10pcs sets Hex Socket Head Bolt M5x25 10pcs sets Lock Washer M5 10sets Propeller Washer M5 Stand Off Engine Mount 1 3 4 44 5mm 4pcs Hex Socket Head Bolt M5x15 10pcs set...

Page 18: ...utput Weight Engine Ignition Module 54 93 cc 3 352 cu in 41 2 mm 1 62 in 41 2 mm 1 62 in 1 500 8 000 r p m 5 5 ps 5 58 hp 7 000r p m 1580 g 55 7 oz 140 g 4 94 oz 60092290 061106 C Copyright 2009 by O S Engines Mfg Co Ltd All rights reserved Printed in Japan TEL 06 6702 0225 FAX 06 6704 2722 6 15 3 Chome Imagawa Higashisumiyoshi ku Osaka 546 0003 Japan URL http www os engines co jp ...

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