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5.5. Engine maintenance
Engines are complexly technical mechanisms with a huge quantity of movable parts. This parts
are partially exposed to high thermal, mechanical and chemical forces. The correct selection
of high quality gasoline and oil as well as accurate maintenance will extend the lifetime of the
engine. Minor reasons could result in big errors due to the total damage of the engine.
Every 2-stroke engine needs three things for the operation:
Ignition, correct gasoline-oil mixture and air
Any case of failure should be examined in the sequence mentioned above.
5.5.1. Ignition
• Unplug the connector from the spark plug.
• Remove the spark plug.
• Check the spark plug electrodes visually. The electrode
gap should be 0,6 - 0,7 mm. The color of the spark plug
should be grey-withe to yellow-grey. There should be
no debris like oil-coil or carbon black.
• Clean the spark plug electrodes carefully with a fine
wire brush. Reset the electrode gap to 0,6 - 0,7 mm
(Ordinary done by light tapping with the back side of
the wire brush on the spark plug electrode).
• Plug the clean spark plug to the connector without screwing them in. Hold the ground elec
-
trode of the spark plug to the engine case. Turn main switch to „ON“ or „I“. Pull the handle
of the recoil starter. You should see sparks between ground and middle electrode. If there
are no sparks you have to replace the spark plug and repeat the testing procedure.
• If the spark plug has to be replaced, please choose one of the following types:
Manufacturer
Type
Original spark plug
Bonon F5TC
NGK
B5ES
If there are no sparks after replacing the spark plug, please check the following:
• Check the connector of the spark plug if there is any damage or humidity (the main switch
must be set to position “ON”).
• If the connector is checked, you have to dismount the fuel tank. Now check CN2-1 and
CN2-2 (connectors of the ignition coil).
• Measure the value of CN2-1 to ground (=engine block) - you should determine a resis
-
tance of 0,3 Ω.
• Measure the value of CN2-1 to spark plug connector - you should determine a resistance
of 2,4 kΩ.
• Check the condition of the spark plug cable (no sore rubs or breakages). Check also the
proper installation of the spark plug connector on the cable (screwed on).
• If the engine still not starts open the air flow cover (recoil starter cover) and remove the
front panel. Open connector CN1-2 (connector of the main switch). Pull the handle of the
recoil starter.
• In case that the ignition of the engine works now, either the cable to the main switch or
the main switch itself has a shortcut to ground. Correct the defects according to the lo-
cated error (see also the electric wiring diagram).
