Sooting of the spark plug:
If you drive your model over a longer period only very slow this may result in a sooting of the spark plug. The consequences are spark failures,
as the case may be the engine can not be started anymore. Combustion residues occur at the bottom of the insulator. The ignition voltage is
now transmitted over the conductive soot film to the ground at the plug thread, but without the desired ignition spark (therefore very small or
weak ignition spark). In this case we recommend to lift the rear wheels of the model and speed up to full throttle repeatedly for a few moments.
This secures that the soot residues are combusted again according to the arising higher temperature. Possibly the spark plug has to be unscre-
wed and cleaned (see picture). In that case proceed as follows: Unscrew the spark plug and press the spark plug socket on the spark plug. Hold
the outside thread of the spark plug with a bared flat pliers against the cylinder and activate the engine with the rope. Now you should be able
to see an ignition spark clearly at the spark plug. If no ignition spark is visible and the annular passage is still highly sooted we recommend to
remove the sedimented oil carbon (sooting) between insulator and housing with a steel needle. Then rinse the annular passage with FG Cleaning
Spray and let it air. Mount the spark plug back in the engine and start it.
Afterwards operate the engine a few seconds at full throttle so that the spark plug is cleaned. For the further use of the engine please see to a
correct carburetor adjustment. Don’t adjust the engine too rich as then the same problem may occur again (see instruction 5. carburetor adjust-
ments). If you operate your model often at low throttle we also recommend to use the FG spark plug 07343/06. This spark plug has a higher
heat range and therefore it reduces the sooting.
Engine has spark failures or no ignition spark:
Check the connection between spark plug and spark plug socket. The spark plug socket must sit firm on the spark plug. If that’s not the case re-
place the spark plug socket against a new one.
Increased and irregular idle speed:
The engine has an irregular increased idle speed. Furthermore it’s very difficult or rather impossible to adjust the carburetor. In that case we re-
commend to check the condition of insulator and carburetor gasket, exchange defective parts if necessary.
