44 Series 4180 Powerhead
– Apply thin coating of sealant to 
gaskets faces, b 12
: Tighten down the screws 
(arrows) in crosswise pattern, 
b 3.4
Always check and, if necessary, 
repair the fuel system, carburetor, 
air filter and ignition system before 
looking for faults on the engine, 
b 4.1
– Remove the lower half of the 
crankcase, b 7.8.2
: Lift the crankshaft (1) and pull the 
piston out of the cylinder at the 
same time.
– Pull off the oil seals (2 and 3).
– Inspect cylinder running face for 
signs of damage and serious 
scores. Install new cylinder if 
necessary, b 7.10
: Examine ball bearings (1), 
connecting rod (2) and gear (3).
– If one of these parts is damaged, 
install a new crankshaft 
assembly. 
– Coat piston and piston rings with 
oil.
– Fit piston rings so that their gaps 
are offset 120 degrees.
– Use new oil seals.
– Lubricate sealing lips of oil seal 
with grease, b 12
– Apply a thin coating of sealant to 
the outside diameter of the oil 
seal, b 12
– Fit oil seals over crankshaft with 
their open sides facing inwards.
 
– Carefully fit piston in the cylinder.
– Install the crankshaft with new oil 
seals.
– Fit lower half of crankcase, 
b 7.8.2
– Install the flywheel, b 7.7
7.8.3 Crankshaft