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Potential Engine issues


possibile cause



cold starting

mixture too rich or too poor


follow the procedures

go to "engine starting"

go to "carburetion"

air bubbles in the circuit

charge the circuit before starting the engine, go to "engine starting"

power failure to the spark

remove it and check

hot starting

mixture too poor

go to "carburetion"

after switching off when the engine is still hot

vapour look

wait few minutes or use a colder spark

different troubles

low battery or failure on the electric circuit

go to power failure

different troubles with float type carburetor

the gas from the float chamber spread on the sump

go to "engine starting"

different troubles with diaphragm carburetor

after a long resting the carburetor is "dried"

go to "engine starting"
UNEVEN POWER (high revs. power loss) AND UNSTEADY IDLING
in case these troubles show simultaneously
carburetion lean because of gas shortagecarburetiongo to "carburetion"
air suction in the fuel circuit replace pipes, filters and joints
obstructions in the fuel flow 
  • replace the gas filter
  • clean the inner filter in the carbutetor
  • clean the needle jets and fuel ways inside the carburetor

go to  carburetor maintenance

the carburetor doesn't provide enough fuel
  • clean the intake pressure hole
  • the carburetor gasket is broken or badly mounted
  • replace the diaphragms *

go to carburetor maintenance

* must be done when fuel swiftly goes back to the fuel tank when switching off the engine
carburetion lean due to an excess of aircarburetiongo to "carburetion"
fuel suction through the sump or its gaskets
  • check and waterproof by suitable products all the junctions and gaskets
  • replace the crankshaft gaskets
 carburetion too richgo to "carburetion"
  • too much oil in the mixture

  • unsuitable oil


spark plug electrodes distance 

0,5 mm (tool supplied)

distance coil / fly-wheel

0,3 ; 0,5 mm

short circuit on the switch off circuit

check thermostat (if any), the switch off button, the insulation of the coil electric wire to the terminal 


to the speed-reducer

oil lack

check the oil level

bearings or gears damaged


to the muffler

mountings or muffler manifold

fix or replace the mountings

muffler ineffectual

replace glass wool


air box disconnectet


to the propeller

 damaged by foreign bodies

fix or replace

before taking off again check the engine bolts and nuts


just started

air on the gasoline lines

increasing the RPM the engine will such off the air