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The choke valve is set to allow minimum air flow only when fully closed, which could cause 
damage to the intake reed valve. 
 
 
Depending on the throttle control used there is a possibility to use throttle stop-screw. 
 

 
If the throttle pull rod is not equipped with flexible element it is recommended NOT to put off 
the  throttle  valve  spring.  Otherwise  the  vibrations  of  the  engine  can  cause  excessive  wear  of 
the throttle valve shafting and with this deteriorate the carburetor function. 

 
 

Adjusting carburetor position 

 

You can turn the rear cover by 90

°

 which makes it possible to adjust the carburetor’s position 

(especially its adjusting needles) when fixing it in the model. 
 
How to dismantle the rear cover: 
Unscrew two M4 screws that hold the carburetor in place, remove the pressure hose from the 
carburetor (mind the gasket under the carburetor), remove the carburetor and loosen four M5 
screws along the crankcase (Caution! Do not loosen the M4 screws that fix the reed-valve to 
the rear cover). 
 
Remove the rear  cover by pulling it out of the crankcase – never use a hammer or any other 
similar tool. The rear cover is sealed in the crankcase with two sealing rings – therefore more 
strength is needed, however, it must always be pull only!  
 
Make sure you disassemble the engine in a clean environment! 
 
Position  the  rear  cover  as  desired,  carefully  insert  it  in  the  crankcase  and  tighten  the  screws. 
Do not forget insert the gasket when reassembling the carburetor.  

 

 
 
 

Starting and running in a new engine 

 
Before you first start the engine, screw the plug in and tighten it up. Follow the instructions on 
the box of the spark plug. Make sure that the plug socket is fitted in place and fastened down 
properly; pull the wire ring over the hexagon. 
Fix the ignition sensor in proper position above the magnet with screws enclosed. 

  

Unless  the  spark  plug  is  not  inserted  in  plug  socket,  never  turn  the  engine  with  ignition 
turned on.  This could lead to ignition damage!
 
 
1) Make sure that the ignition is switched off, the choke valve is closed and the throttle valve 
is  about  half  opened.  Then  give  the  engine  3-4  turns,  provided  that  carburetor  is  not 
overflowing. If it is overflowing, only give the engine 1-2 turns. 
 
2)  Switch  the  ignition  on,  open  the  choke  valve,  set  the  throttle  at  slightly  higher  idle  speed 
and  give  the  engine  a  few  quickly  turns.  If  even  after  the  fourth  turn,  with  the  choke  valve 
closed, you do not hear a suggestion of the engine starting, give the engine 2 turns following 
the  instructions  in  paragraph  1  above.  Then  proceed  according  to  instructions  given  in 
paragraph 2. 
 
3) If the engine does not start even after another set of turns open the throttle to maximum and 
give  the  engine  approx.  4  turns.  Switch  the  ignition  off  and  on  again  and  restart  the  engine 
with throttle turned slightly down and the choke valve set open.  
 
4)  If  the  engine  still  would  not  start,  unscrew  the  plug  and  check  its  contacts.  Clean  any 
possible petrol moisture (i.e. an indication of engine overflow) and screw it in again. Further 
starting should only be done with the throttle turned down. If the plug is dry then probably not 
enough fuel has been drawn into the carburetor. If that is the case, check the fuel feed and then 
return to the instructions given in paragraph 1.  
 
If the engine starts to run backwards do not open the throttle - stop the engine immediately! 
Otherwise the engine can be damaged! 
 
Having started the engine, leave it running for approx. 2 min at a higher idle speed. Then run it 
in for approx. 20 min, while changing revolutions from idle to 1/2-3/4 of the range and shortly 
holding each position - gradually prolong the holding periods. After 10 min of operation start 
opening  the  throttle  at  maximum  for  short  periods  of  time.  Stop  the  engine  and  let  it  cool 
down. Then restart it and check the adjustment. If everything is all right, you can first take off. 
During first few flights do not overload the engine and do not let it run at high revolutions for 
long  periods of  time  (very  important  at  hot  weather).  Use  up  all  fuel  that  was  produced  as  a 
mixture with the oil that is included in the package. From now on, fuel and oil should be mixed 
in the proportion 40:1.    
 

 

DO NOT PROCESS THE RUNNING-IN AT IDLE SPEED! 

 

A COLD ENGINE SHOUL BE WARMED UP BY SHORT 
ACCELERATIONS (1-2 SECONDS)  

Throttle stop 
screw 

Throttle lever 
spring 

Summary of Contents for 58 IRS - V1.7

Page 1: ...available power output Safety precautions 1 Never use the engine for any manned vehicles 2 When operating model planes always follow the rules and laws in effect in your country 3 The manufacturer declines all responsibility for all damages arising from the operation of models and other appliances droved by MVVS 58 engine 4 Always use original spare parts 5 Never tamper with the engine constructio...

Page 2: ...g on the speed of flight on the ground We do not recommend using propellers with which the engine reaches more than 7500 RpM on the ground Fuel Always use unleaded 95 octane petrol mixed in the proportion 40 volume units of petrol to 1 unit of Mobil Racing 2T oil If necessary quality brand name synthetic oil intended for racing two stroke engines can be used too Running the engine in use MVVS Raci...

Page 3: ... If acceleration is smooth open the needle by another 3 5 min this should be done because the needle was previously set at a boundary value if atmospheric conditions changed during flight the problems might recur If the engine still has bad acceleration open the needle by 10 min 60 degree If the engine s operation does not improve afterwards stop it and check the basic setting Set the adjusting ne...

Page 4: ... opened Then give the engine 3 4 turns provided that carburetor is not overflowing If it is overflowing only give the engine 1 2 turns 2 Switch the ignition on open the choke valve set the throttle at slightly higher idle speed and give the engine a few quickly turns If even after the fourth turn with the choke valve closed you do not hear a suggestion of the engine starting give the engine 2 turn...

Page 5: ...embrane and gasket in a correct order recheck the pressure hose attached to the carburetor Replacing the reed valve unscrew and remove the carburetor mind the gasket unscrew four M4 screws on the flange remove the flange and take off the reed valve mind the gasket unscrew four M2 screws and remove the old valves replace them with new ones screw the screws back in and tighten them gently when reass...

Page 6: ...14S Electronic ignition unit ProSport LE 0702 Piston ring 3309 Spark plug 0801 Piston pin 1405 Ignition sensor fixing screws 0802 Piston pin retainer 3227 Carburetor Warranty The MVVS gas engines come with a three year guarantee against defects in workmanship and materials Only original buyers of the engines are eligible warranty claimants The warranty cannot be transferred with a change in owners...

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