Assembling - Evinrude 4906B 4HP 1969 Owner's Manual

3-24 POWERHEAD
Check the piston ring grooves for wear,
burns, distortion or loose
During an overhaul,
replaced to ensure lasting repair and proper
engine performance
completed.
Clean the piston dome, ring grooves and
the piston skirt. Clean the piston skirt with
a crocus doth.
Clean carbon deposits from the top of
the piston using a soft wire brush, carbon
removal solution, or by sand blasting.
wire brush is used, TAKE CARE not to burr
or round machined edges.
Wear a pair of good gloves for protection
against sharp edges, and dean
ring grooves using the recessed
proper broken ring as a tool.
rectangular ring to clean the groove for a
tapered ring, or use a tapered ring to clean
the groove for a rectangular
NEVER use an
groove cleaner to clean piston ring grooves,
because this type of tool could loosen the
piston ring locating pins.
to burr or round the machined edges.
spect the piston ring locating pins to be sure
they are tight. There is one locating pin in
each ring groove.
loose, the piston must be replaced.
attempt to replace
successful.
Oversize Pistons and Rings
Scored cylinder blocks can be saved for
further service by reboring
Cleaning the piston ring grooves.
type ring groove cleaner should NEVER be used.
locating pins.
the rings should be
after the work has been
If a
the piston
end of the
NEVER use a
ring.
automotive-type ring
TAKE CARE not
If one locating pin is
Never
the pin, it is NEVER
and installing
An automotive
a
Using micrometer
piston.
oversize pistons
MORE WORD:
are not available
time of this printing, the sizes listed in the
In- Appendix were available.
parts department
the model engine you are servicing,
be sure the factory
from their stock.

ASSEMBLING

CRITICAL
Two conditions
when the piston and rod assembly are instal-
led into the cylinder block.
The slanted side of the piston must face
toward the exhaust side of the cylinder.
The hole in the rod near the wrist pin
opening and at the lower end of the rod
must face UPWARD.
An automotive
used to install the rings for
to
check the roundness
and piston. rings.
Oversize pistons and rings
for all engines.
Check with the
at your local dealer for
has not deleted a size
WORDS
absolutely
ring compressor should
a two-cycle engine.
of
the
ONE
At the
and to
MUST exist
NEVER
be