3.4.4.2 Spark Plug Installation and Removal
To remove spark plugs, disconnect the spark plug cap. Loosen spark plug with spark plug
wrench and unscrew.
Before installing the new or still usable spark plug, the electrode gap (0.8 mm) has to be
checked with a feeler gauge and adjusted as required.
Screw the spark plug into the cylinder head with a spark plug wrench, then use a torque
wrench to insure the prescribed torque.
3.4.4.3 Condition of Spark Plugs
Spark plugs should have a dry, light brown color at the center electrode, the isolator of the
center electrode and the main housing. If the color goes into a light, very dry grey, the engine
is running very hot and the mixture is too lean. When the color is a wet, dark brown to black,
the engine is running too rich. In both cases, the dealer or manufacturer should be contacted.
Check over the center electrode and the ground electrode for deterioration (oxidation). If
oxidation is visible, the spark plug must be replaced immediately. Absolutely refrain from
cleaning spark plugs with abrasive objects such as sand paper or wire brush.
3.4.5 Fan
It is necessary that the opening for the fan remain unobstructed. Only sufficient flow of fresh
air and satisfactory operation of the fan can guarantee proper cooling of the engine.
3.4.5.1 Removal and Installation of Cooling System Cowl
For removal of the cowl, pull off the spark plug caps and unscrew spark plugs. Mark position
of the spark plug caps. Remove entire muffler after the elbow in the exhaust manifold (see
later chapter). Remove both screws to the crankshaft housing underneath the elbow of the
exhaust manifold. Then remove the screws to the fan housing on the side of the cool air exit.
Pull off the shroud over the elbow of the exhaust manifold. To install the shroud, reverse the
process used for removal. Should there be any damage to the shroud, it has to be replaced
immediately.
3.4.5.2 Removal and Installation of Fan Housing
To remove the fan housing, take out the screws of the shroud on the side of the cool air exit.
Turn the excenter of the fan wheel so that the flat belt of the fan is without tension. Remove
the four front screws of the fan housing and pull the shroud off along the axis of the adapter
sleeve. After the fan housing slips off the adapter sleeves, push the fan housing downward and
take the flat belt off the belt disk. To install the fan housing, reverse this process in logical
order. Turn the excenter of the fan wheel and set to maximum tension.
3.4.5.3 Changing the Fan Belt
To change the fan belt, take out the fan housing (see previous section). Cut up frayed fan belt
and remove from fan housing. Remove the shroud with a screw driver and wrench. Put a
new flat fan belt into one of two slits of the fan housing and hang it into one of the wings of
the fan blades and slowly turn the fan blade. The other fan blades of the fan wheel have to
always run between the belts. After three quarter turns of the fan wheels, insert the part of the
belt that is outside into the other slit in the fan housing and then remount the metal guard.
