3.4.6 Cylinder Head
The cylinder heads are composed of a special aluminum alloy which permits maximum
temperature of 280 degrees C. If the metal is overheated (ca. 300 degrees C) it will lose its
hardness. This will lead to leaks in the seal between cylinder head and cylinder. Tightening
of the cylinder head screws will have no effect. The cylinder head has to be replaced.
3.4.6.1 Cylinder Head Removal and Installation
To remove the cylinder head, remove the spark plug caps, the spark plugs, and the fan
housing, as described above. Loosen and unscrew the eight cylinder head screws with a
hexagonal socket wrench. Mark the position and placement of the cylinder heads, then
remove cylinder heads. To install the cylinder heads, reverse the process, tightening the
cylinder head screws lightly and first, then applying the prescribed torque values using
crossway technique.
3.4.6.2 Checking Cylinder Head Condition
Check the seal of cylinder heads and cylinders for places on which exhaust gas has blown
through. These places can be recognized by black lines over the seal and burned residue on
the cooling fins. Should there be such places, the cylinder head must be immediately
replaced. Check the indentation on the cylinder head for the black residue. If present, remove
it and eventually change the type of oil used.
3.5 Trouble Shooting
3.5.1 Engine Does Not Start or is Difficult to Start
Cause:
-Lack of fuel
Solution:
-Insure fuel switch is on
-Insure
fuel
filter
is
clean
-Insure that fuel is in the tank
Cause:
-Defective or discharged battery
Solution: -Replace
battery
-Charge
the
battery
Cause:
-Lack of compression on one or both cylinders, due to a loose spark plug or a
defective piston, piston ring, cylinder head, or cylinder
Solution:
-Tighten spark plug to prescribed torque, or ship engine to the manufacturer or
an authorized Hirth service center
Cause:
-No spark or weak spark due to defective spark plug, spark plug cap, or a
defective ignition
Solution:
-Replace spark plug, spark plug cap, or have the manufacturer or an authorized
Hirth service center replace the defective ignition