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18

10  Plug wrench

Used for tightening glowplug. The 
O.S. long plug wrench is available 
as an optional accessory.

7  Fuel pump

For  filling  the  fuel  tank  one  of  the 
purpose-made manual or electric fuel 
pumps may be used to transfer fuel 
directly from your fuel container to the 
fuel tank.

For tightening
glowplug

Manual

Electric

Fuel pumps

Fuel Can Filter

8  Fuel container filter

Install a filter on the outlet tube of your 
refuelling container to prevent entry of 
foreign matter into the fuel tank

9  Silicone tubing

This  is  required  for  the  connection 
between the fuel tank and engine.
ID  2.5mm  and  OD  5-5.5mm  one 
would be suitable.

Silicone tubing

2x   5xL12mm

Silicone Tube

Joint Nipple

(Joint nipple and silicone tube are fit
 on the cover plate.)

If  the  silicone  tube  on  the  cover  plate  is  damaged, 
use  commercially  available  2mm  ID  and  5mm  OD 
silicone tube by cutting to 12mm length.

19

FACTS ABOUT GLOWPLUGS

The role of the glowplug

Glowplug life

Particularly  in  the  case  of  very  high  performance 
engines, glowplugs must be regarded as expendable 
items.

With  a  glowplug  engine,  ignition  is  initiated  by  the 
application  of  a  1.5-volt  power  source.  When  the 
battery is disconnected, the heat retained within the 
combustion chamber remains sufficient to keep the 
plug filament glowing, thereby continuing to keep the 
engine running. Ignition timing is 'automatic' : under 
reduced load, allowing higher rpm, the plug becomes 
hotter  and,  appropriately,  fires  the  fuel/air  charge 
earlier; conversely, at reduced rpm, the plug become 
cooler and ignition is retarded.

Since the compatibility of glowplug and fuel may have 
a marked effect on performance and reliability, it may 
be  worthwhile  to  choose  the  R/C  type  plug  found 
most  suitable  after  tests.  Recommended  O.S.  plugs 
are  No.8  and  A5.  Carefully  install  plug  finger-tight, 
before  final  tightening  with  the  correct  size  plug 
wrench.

Install a plug suitable for the engine.

Use  fuel  containing  a  moderate  percentage  of 
nitromethane.

Do not run the engine too lean and do not leave the 
battery connected while adjusting the needle. 

However,  plug  life  can  be  extended  and  engine 
performance maintained by careful use, i.e.:

Apart  from  when  actually  burned  out,  a  plug  may 
need to be replaced because it no longer delivers its 
best performance, such as when:

When to replace the glowplug

Filament surface has roughened and turned white. 

Filament coil has become distorted.

Foreign  matter  has  adhered  to  filament  or  plug 

body has corroded.

Engine tends to cut out when idling.

Starting qualities deteriorate.

Summary of Contents for MAX-91SX-HRING C Spec PS VIPER

Page 1: ...LE SERVO CARE AND MAINTENANCE EXPLODED VIEW PARTS LIST O S GENUINE PARTS ACCESSORIES THREE VIEW DRAWING MEMO 7 8 13 16 30 10 36 22 24 24 27 29 32 35 37 38 It is of vital importance before attempting t...

Page 2: ...many other possibilities generally less obvious sources of danger but which under certain circumstances may also cause damage or injury 3 WARNINGS Never touch or allow any object to come into contact...

Page 3: ...head down securely Take care that the glow plug clip or battery leads do not come into contact with rotating parts Adjust the throttle linkage so that the engine stops when the throttle stick and tri...

Page 4: ...oove onto the connecting rod BDC position Rotate the crankshaft so that the connecting rod comes to this position 7 Note on installing the engine Note on heating the glow plug Cooling fan cover from s...

Page 5: ...h torque type starter DO NOT however confuse tightness with the symptoms of hydraulic lock caused by an excess of fuel within the cylinder often the result of over priming Attempting to force the engi...

Page 6: ...the under surfaces of the engine s mounting lugs are in contact with the engine mount 11 ABOUT THE PUMP SYSTEM Please understand the pump construction before piping Pump functions in accordance with t...

Page 7: ...el in the pump Stop the fuel flow to the pump with the stopper and run the engine at idling to use out the fuel in the pump After stopping the engine rotate the engine by electric starter to eject fue...

Page 8: ...1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1...

Page 9: ...and connections carefully for any cracks on the tubes and loose connections as the engine runs ejecting excess fuel 17 4 Glowplug battery The power source for heating the glowplug may be either a lar...

Page 10: ...is disconnected the heat retained within the combustion chamber remains sufficient to keep the plug filament glowing thereby continuing to keep the engine running Ignition timing is automatic under re...

Page 11: ...Ixture Control Screw Lean With a model helicopter adjustments may vary due to various factors such as climatic conditions fuel muffler main rotor weight of the model gear ratio etc 89 degrees When the...

Page 12: ...ating a dangerous situation 23 In case the engine does not stop Hold the rotor head and pinch the fuel line to stop the fuel supply If it still does not stop pull off the fuel line from the carburetor...

Page 13: ...15 30 nitromethane Bear in mind that fuels containing relatively large percentages of power boosting nitromethane operate at richer mixture settings than are needed for mild fuels and will therefore r...

Page 14: ...se at medium r p m e g hovering speeds is most important since this is a power range widely used in helicopter flight The optimum fuel air nixture strength at medium speeds is dependent on obtaining b...

Page 15: ...mostly accumulate here SUBSEQUENT READJUSTMENTS Once the engine has been run in and the carburetor controls properly set up it should be unnecessary to alter the mixture settings except to make minor...

Page 16: ...re Close the High Speed Needle Valve Turn clockwise Land the model Idle for approx 10 seconds then reopen throttle to observe transition Float the model Idling OK Lean mixture Rich mixture High Speed...

Page 17: ...ide your refueling container will prevent the entry of foreign material into the fuel tank It is also recommended that a good in line filter be installed between the tank and carburetor 1 Finally inje...

Page 18: ......

Page 19: ...881810 27881800 27881820 45581820 29084100 27881330 27681340 27081900 27981910 24981837 46181940 46181941 26711305 46181950 Ratchet Spring Needle Needle Valve Assembly Fuel Inlet Rotor Guide Screw O R...

Page 20: ...MP 10set Cap Screw Set M2 6x5 10pcs set 79871010 M3 5x10 79871070 7091 71530500 For 70SZ H 91SX H Needle Adjusting Screw 5pcs M2 6x5 41621100 37 THREE VIEW DRAWING Displacement Bore Stroke Practical R...

Page 21: ...d 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 U N E Q U A LLEDQ U A LIT Y P R E C IS IO N P E R F O R M A N C...

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