page 46
Release 00 - 03/2018
Engine TRE 224
Workshop Manual
15.3. Dismantling and checking the piston, piston
rings, connecting rod and engine shaft
NOTA: These paragraphs describe all the
operations for checking and overhauling the
thermal components of the engine; it is left
to the operator to assess the advisability of
performing all the operations described or
only part of them, depending on the type of
engine problems encountered.
All the following operations on the grass cutter ne-
cessitate the removal of the motor.
NOTE: For engine removal operations you
should consult the manual specific to
the machine on which the engine itself is
mounted.
1 - Remove the magneto flywheel
.
3 - Remove the camshaft
4 - Dismantle the cap (16) of connecting rod (17)
fixed with two screws (18) (take note of any refe-
rence marks for refitting).
5 - Push the connecting rod (17) so as to cause the
piston (19) to come out of the cylinder (20).
6 -
Use the special expanding tool (21) to re-
move the two compression rings and the oil scraper
ring from the piston (19).
7 - Carefully remove all carbon deposits from the
compression rings, the inside of the cylinder and
the piston head.
8 - To check the wear in the compression rings, insert
them one at a time into the cylinder (20) by about
10-15 mm and measure the gap between the two
ends with a feeler gauge (22); the rings must be
replaced if the gap is more than 1 mm.
NOTE: If a gap of more than 0.6 mm is measu-
red with new rings it means that the cylinder is
worn beyond the acceptable limits and must
be replaced. The cylinder must be replaced
if it shows striping due to a seizure.
15. ENGINE BLOCK - Overhauling internal parts
18
17
16
21
19
19
20
22
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