Evinrude 4906B 4HP 1969, Owner'S Manual

Page: 60 / 422

It may be necessary to heat the piston in
a container of boiling water in order to
press the wrist pin free.
Remove the retaining clips from each
end of the wrist pin. Some clips are spring
wire type and may be worked free of the
piston using a screwdriver. Other model
pistons have a truarc snap ring. This type of
ring can only be successfully removed using
a pair of truarc pliers.
Place the piston in an arbor press using
the PROPER size cradle for the piston being
serviced, and with the LOOSE
side
of the
piston facing UPWARD.
The wrist pin must be driven out FROM
the loose side. This may not seem reason-
able, but there is a very simple explanation.
By placing the piston in the arbor press
cradle with the tight side down, and the
arbor ram pushing from the loose side, the
piston has good support and will not be dis-
torted. If the piston is placed in the arbor
press with the loose side down, the piston
would be distorted and unfit for further
ser vice.
Many rods have a wrist pin bearing.
Some are caged bearings and other are not.
Heating
a
piston in hot water
to
expand the metal
slightly.
RODS AND PISTONS 3-19
TRUARC
SNAP RING
Removing the wrist pin truarc snap ring from the
piston.
Snap ring used
to
retain the wrist pin in the piston.
Removing a snap ring with a pointed tool.