Evinrude 4906B 4HP 1969 Owner's Manual page 45

3-4 POWERHEAD
bustion portion of the cylinder and is com-
pressed, as the piston moves upward.
This particular powerhead does not have
intake cover plates, because the intake passage
is molded into the cylinder wall as described in
the previous paragraph.
powerheads and being serviced, disregard the
sections covering intake cover plates.
3-2 CHAPTER ORGANIZATION
This chapter is divided into
service sections.
particular area of service and outlines com-
plete instructions for the work to be per-
formed. Because of the
number of outboard
would be impractical
to give detailed procedures for removal and
installation of each bolt, carburetor,
er, and other "buildup" type units.
Therefore, the sections, for the particu-
lar powerhead work to be performed,
with the preliminary
ed. As an example,
powerhead begins with the necessary
cowling, and accessories
Armature plate prior to powerhead
Therefore, if these
14 main
Each section covers a
many countless
units in the field, it
and almost impossible
start-
begin
access tasks complet-
disassembly of the
hood,
removed.
disassembling.
The information
sequence for complete power head overhaul.
The instructions can be followed generally
for almost any size horsepower engine.
rare cases, where the procedures
pending on the model being serviced, separ-
ate steps are included.
three different type of crankshaft
tions.
The illustrations
are from different
tions clearly identify which model is cover-
ed.
Exploded drawings,
parts, for the various
included at the end of the chapter.
Special tools may be called out in cer-
tain instances. These tools may be purchas-
ed from the local Johnson/Evinrude
or directly from Customer Services Depart-
ment, Outboard Marine Corporation
Waukegan, Illinois, 60085.
The chapter ends with
dures, Section 3-16, to be performed
the powerhead has been assembled,
cessories installed,
mounted on the exhaust housing.
Tor-que Values
All torque values must be met when they
are specified. Many of the outboard cast-
ings and other parts are made of aluminum.
The torque values
stretching the bolts, but more importantly
to protect the threads in the aluminum.
is extremely important
necting rods to the proper torque value to
ensure proper service.
probably the next most important
value.
Power-head Components
Service procedures
fuel pumps, starter,
components are given in their
chapters of this manual.
Contents.
Reed Installation
All reeds on Johnson/Evinrude
covered in this manual are installed
behind the carburetor
manifold.
Cleanliness
Make a determined
and the work area
is presented in a logical
differ de-
One example is the
installa-
accompanying the text
size units and the cap-
showing principle
size power heads are
dealer
(OMC),
Break-in Proce-
after
all ac-
and the powerhead
are given to prevent
to tighten the con-
The head bolts are
torque
for the carburetors,
and other powerhead
respective
See the Table of
engines
just
behind the intake
effort to keep parts
as clean as possible.
In
It