Evinrude 4906B 4HP 1969 User manual

TABLE OF CONTENTS
1
S FETY
TOP SEAL
3 12
Removal
3 12
INTRODUCTION
1 1
BOTTOM SEAL
3 13
CLEANING, WAXING, Inspection
3 14
AND POLISHING
1 1
CENTERING PINS
3 15
CONTROLLING CORROSION
1 2
PROPELLERS
1 2
MAIN BEARING BOLTS
FUEL SYSTEM
1 7
AND CRANKCASE SIDE BOLTS
3 15
LOADING
1 9
CRANKCASE COVER
3 16
HORSEPOWER
1 10
Removal
3 16
FLOTATION
1 10
Cleaning and Inspecting
3 16
EMERGENCY EQUIPMENT
1 12
CONNECTING RODS
COMPASS 1 15
AND PISTONS 3 16
STEERING
1 17
Removal
3 17
ANCHORS
1 17
Disassembly 3 18
MISCELLANEOUS EQUIP MENT
1 18
Rod Inspection
BOATING ACCIDENT REPORTS
1 19
and Service 3 21
NAVIGATION
1 19
Piston and Ring Inspection
and Service 3 22
2 TUNING Assembling
3 24
CRANKSHAFT
3 27
INTRODUCTION
2 1
Removal
3 27
TUNE-UP SEQUENCE
2 2
Cleaning and Inspection
3 27
COMPRESSION CHECK
2 3
Assembling
3 28
SPARK PLUG INSPECTION
2 4
IGNITION SYSTEM
2 4
CYLINDER BLOCK SERVICE 3 28
SYNCHRONIZING
2 5
Honing Procedures 3 29
BATTERY SERVICE
2 5
Assembling 3 30
CARBURETOR ADJUSTMENTS
2 7
Piston and Rod Assembly
FUEL PUMPS
2 9
Installation 3 30
STAR TER AND SOLENOID
2 10
Crankshaft Installation
INTERNAL WIRING HARNESS
2 11
Large Horsepower Engines
WATER PUMP CHECK
2 12 15
hp to 4 0 hp
3 33
PROPELLER
2 13
Crankshaft Installation
LOWER UNIT 2 14
Small Horsepower Engines
BOAT TESTING
2 15 1.5
hp, 5.0 hp, 5.5 hp,
6.0 hp, 9.5 hp 3 35
3
POWERHE D Crankshaft Installation
Small Horsepower Engines
INTRODUCTION
3 1 3.0
hp, 4 .0 hp, 7.5 hp
3 37
Theory of Operation
3 1
Crankcase Cover Installation
3 38
CHAPTER ORGANIZATION
3 4
Main Bearing Bolt and Crankcase
POWERHEAD DISASSEMBLING
3 5
Side Bolt Installation 3 39
HEAD SERVICE
3 5
Bottom Seal Installation
REED SERVICE
3 6 15
hp to 4 0 hp Engines 3 39
Description
3 6
Exhaust Cover and Bypass
Reed Valve Adjustment
3 8
Cover Installation
3 4 0
Cleaning and Service
3 9
Reed Box Installation
3 4 0
BYPASS COVERS
3 10
Head Installation
3 4 1
EXHAUST COVER
3 11
BREAK-IN PROCEDURES
3 4 1
Cleaning
3 11
EXPLODED DRAWINGS
3 4 2 3 50

.
FUEL
SYNCHRONIZA TION FUEL AND
IGNITION SYSTEMS
5 26
INTRODUCTION
4 1
Primary Pickup Adjustments
GENERAL CARBURETION and Locations
5 26
INFORMATION
4 1
FUEL SYSTEM
4 4
6
ELECTRICAL
TROUBLESHOOTING
4 4
Fuel Pump Tests
4 6
INTRODUCTION
6 1
Fuel Line Test
4 7
BATTERIES
6 1
Testing with Pressure Tank
4 8
Mar ine Batteries
6 1
Rough Engine Idle
4 10
Battery Construction
6 2
Excessive Fuel Consumption
4 11
Battery Location
6 2
CARBURETORS
4 12
Battery Service
6 2
TYPE I CARBURETOR
4 13
Jumper Cables
6 5
Removal and Disassembling
4 13
Dual Battery Installation
6 5
Cleaning and Inspecting
4 15
GAUGES AND HORNS
6 7
Assembling
4 16
Constant-Voltage System
6 7
CHOKE SYSTEM SERVICE
4 23
SERVICE PROCEDURES
6 7
Heat/Electric Choke
4 23
Temperature Gauges
6 7
All Electric Choke
4 25
Warning Lights
Water Choke
4 26
Thermomelt Sticks
6 8
TYPE II CARBURETOR
4 28
FUEL SYSTEM
6 8
Disassembling
4 28
Fuel Gauge
6 8
Cleaning and Inspecting
4 31
Fuel Gauge Hookup
6 8
Assembling
4 33
Troubleshooting
6 9
ASSEMBLING CHOKES TO TACHOMETER
6 10
TYPE II CARBURETORS
4 38
HORNS
6 10
Adjustments
4 42
ELECTRICAL SYSTEM GENERAL
TYPE III CARBURETORS
4 43
INFORMA TION
6 11
Removal
4 4 3
CHARGING CIRCUIT SERVICE
6 12
Cleaning and Inspecting
4 45
Troubleshooting
6 12
Assembling
4 47
Generator Service
6 16
Adjustments
4 50
Armature Testing
6 17
FUEL PUMP SERVICE
4 51
Cleaning and Inspecting
6 18
Troubleshooting
4 52
Assembling
6 20
Removal and Repair
4 52
CHOKE CIRCUIT SERVICE
6 22
Cleaning and Inspecting
4 54
STARTER MOTOR CIRCUIT
Assembling and Installation
4 54
SERVICE
6 22
FUEL TANK AND LINE SERVICE
4 57
Circuit Description
6 22
Disassembling
4 58
Starter Motor Description
6 22
Cleaning and Inspecting
4 61
Troubleshooting
6 24
Assembling
4 61
Testing
6 25
LATE MODEL FUEL TANK STARTER DRIVE GEAR SERVICE
6 26
SERVICE
4 67
Starter Removal
6 26
5 IGNITION
Drive Gear Disassembling
6 27
Cleaning and Inspecting
6 27
INTRODUCTION
5 1
Assembling Type I Drive
6 28
SPARK PLUG EVALUATION
5 2
Disassembling Type II
6 28
POLARITY CHECK
5 3
Cleaning and Inspecting
6 28
WIRING HARNESS
5 4
Assembling Type II Drive
6 28
FLYWHEEL MAGNETO IGNITION
5 5
DELCO-REMY SERVICE
6 29
TROUBLESHOOTING
5 6
Removal
6 29
SERVICING FLYWHEEL MAGNETO Disassembling
IGNITION SYSTEM
5 13 6 29
Removal
5 13
Armature Testing
6 30
Cleaning and Inspecting
5 19
Cleaning and Inspecting
6 31
Assembling
5 20
Assembling
6 32

6 ELECTRICAL (CONT)
AUTOLITE STARTER MOTOR
SERVICE 6-34
Removal 6-34
Disassembling 6-35
Armature Testing 6-35
Cleaning and Inspecting 6-37
Assembling 6-37
PRESTOLITE STARTER MOTOR
SERVICE 6-39
Removal 6':'39
Disassembling 6-40
Armature Testing 6-40
Cleaning and Inspecting 6-42
Assembling 6-43
STARTER MOTOR TESTING 6-44
STARTER MOTOR
INSTALLATION 6-44
7 ACCESSORIES
INTRODUCTION
SHIFT BOXES
Description
OLD-STYLE DOUBLE LEVER
Troubleshooting
Disassembling
Cleaning and Inspection
Assembling
NEW-STYLE SHIFT LEVER
Troubleshooting
Removal
Disassembling
Cleaning and Inspecting
Assembling
ELECTRIC GEAR BOXES AND
SINGLE LEVER CONTROL 7-12
Troubleshooting 7-12
Disassembling 7-14
Cleaning and Inspecting 7-15
Assembling 7-16
PUSH BUTTON SHIFT BOX SERVICE
EVINRUDE UNITS ONLY 7-18
Troubleshooting 7-19
Disassembling 7-21
Cleaning and Inspecting 7-22
Assembling 7-22
CABLE END FITTING INSTALLA-
TION AT THE ENGINE END 7-24
8· LOWER UNIT
7-1
7-1
7-1
7-3
7-3
7 4
7 5
7-5
7-6
7-6
7-8
7-8
7 9
7-10
DESCRIPTION
Chapter Coverage
Illustrations
TROUBLESHOOTING
MANUAL SHIFT
PROPELLER REMOVAL
8-1
8-1
8 2
8 2
8 7
DRAINING LOWER UNIT
LOWER UNIT SERVICE
1.5 hp to 4.0 hp -- NO SHIFT
Lower Unit Removal
Water Pump Removal
Disassembling
Cleaning and Inspecting
Assembling
Water Pump Installation
Lower Unit Installation
Filling the Lower Unit
Propeller Installation
LOWER UNIT SERVICE
MANUAL SHIFT -- 5 HP
TO 25 HP
Removal
Water Pump Removal
Disassembling
Cleaning and Inspecting
Assembling
Water Pump Installation
Lower Unit Installation
LOWER UNIT SERVICE
MANUAL SHIFT -- 28 HP
TO 40 HP
Removal
Water Pump Removal
Disassem bling
Cleaning and Inspecting
Assembling
Lower Unit Installation
ELECTROMA TIC LOWER UNIT
Description
Troubleshooting
Removal
Disassembling
Cleaning and Inspecting
Assembling
Water Pump Installation
Lower Unit Installation
9 HAND STARTERS
INTRODUCTION
Operation
TYPE I STAR TER
CYLINDER WITH PINION GEAR
5 HP and 6 HP ENGINES
Starter Rope Replacement
Removal
Installation
Starter Removal
Disassembling
Cleaning and Inspecting
Assembling
8-8
8-8
8-9
8 9
8-10
8-11
8-13
8-14
8-15
8-16
8-16
8-17
8-19
8-19
8-20
8-22
8-28
8-31
8-33
8-36
8-37
8-38
8-38
8-41
8-46
8-50
8-53
8-53
8-53
8-56
8 57
8-65
8-66
8-72
8-74
9-1
9 2
9-3
9 4
9 4
9 4
9 5
9 7
9 7
9 7

9 HAND STARTERS (CONT)
- TYPE I STARTER
CYLINDER WITH PINION GEAR
ALL 9.5 HP ENGINES 9-11
Starter Rope Replacement 9-11
Removal 9-11
Installation 9-12
Starter Removal 9-12
Cleaning and Inspecting 9-14
Assembling 9-14
Installation 9-15
TYPE II STARTER
COIL SPRING WITH SWING ARM
DRIVE GEAR
3HP1968
4 HP 1969-70
Removal
Disassembling
Cleaning and Inspecting
Assembling
TYPE III STARTER
MOUNTED ATOP FL YWHEEL
MODEL WITH RETURN SPRINGS
28 HP 1962-63
30 HP1956
35 HP 1957-59
40 HP 1960-63
Removal
Cleaning and Inspecting
Assembling
Rope Installation
Starter Installation
TYPE III STARTER
MOUNTED ATOP FLYWHEEL
MODEL WITH NO RETURN SPRINGS
28HP1964
33 HP 1965-70
40 HP 1964-70
Removal
Cleaning and Inspecting
Assembling
Rope Installation
Starter Installation
TYPE III STARTER
MOUNTED ATOP FLYWHEEL
MODEL WITH ONE NYLON PAWL
3 HP 1956-68
5.5 HP 1956-64
7.5 HP 1956-58
10 HP 1956-63
15 HP 1956
18 HP 1956-70
20 HP 1966-70
25 HP 1969-70
9-17
9-17
9-17
9-20
9-20
9-23
9-24
9-26
9-27
9-29
9-30
9-31
9-32
9-34
9-34
9-37
9 39
9-39
Removal 9-40
Disassembling 9-40
Cleaning and Inspecting 9-42
Assembling 9-43
Rope Installation 9-43
Starter Installation 9-46
10 MAINTENANCE
INTRODUCTION
ENGINE SERIAL NUMBERS
FIBERGLASS HULLS
ALUMINUM HULLS
BELOW WATERLINE SERVICE
SUBMERGED ENGINE SERVICE
WINTER STORAGE
LOWER UNIT SERVICE
Propeller
BATTERY STORAGE
PRESEASON PREPARATION
10-1
10-2
10-3
10-3
10-4
10-5
10-7
10-9
10-9
10-13
10-13
APPENDIX
METRIC CONVERSION CHART
DRILL SIZE CONVERSION CHART
TORQUE SPECIFICATIONS
POWERHEAD SPECS
TUNE-UP SPECS
GEAR OIL CAPACITIES
STARTER MOTOR SPECS
REGULA TOR SPECS
GENERATOR SPECS
CONDENSER SPECS
STAR TER ROPE SPECS
A-I
A-2
A-3
A-4 & A-5
A-6 to AI0
A-ll
A-12
A-12
A-12
A-13
A-14
WIRE INDENTIFICATION ORA WINGS
20 hp and 25 hp -- 1971-72 A-15
33 hp with Generator -- 1965-67 A-16
33 hp with Generator -- 1968 A-17
33 hp with Generator -- 1969-70 A-18
35hp--1957-59 A-19
40 hp Standard Shift
with Generator -- 1960-66 A-20
40 hp Standard Shift
with Generator -- 1967-68 A-21
40 hp Standard Shift
with Generator -- 1969-70 A-22
40 hp Electric Shift
with Generator -- 1961-66 A-23
40 hp Electric Shift
with Generator -- 1967-68 A-24
40 hp Electric Shift
with Generator -- 1969-70 A-25

1
SAFETY
1-1 INTRODUCTION
Your boat probably represents a sizeable
investment for you. In order to protect this
investment and to receive the maximum
amount of enjoyment from your boat it must
be cared for properly while being used and
when it is out of the water. Always store
your boat with the bow higher than the stern
and be sure to remove the transom drain
plug and the inner hull drain plugs. If you
use any type of cover to protect your boat,
plastic, canvas, whatever, be sure to allow
for some movement of air through the hull.
Proper ventilation will assure evaporation of
any condensation that may form due to
changes in temperature and humidity.
1-2 CLEANING, \VAXING, AND POLISHING
An outboard boat should be washed with
clear water after each use to remove sur-
face dirt and any salt deposits from use in
sal t water. Regular rinsing will extend the
time between waxing and polishing. It will
also give you pride of ownership , by
having a sharp looking piece of equipment.
Elbow grease, a mild detergent, and a brush
Whenever the boat is stored, for long or short
periods, the bow should be slightly higher than the stern
and the drain plug in the transom removed to ensure
proper drainage of rain water.
will be required to remove stubborn dirt, oil,
and other unsightly deposits.
Stay away from harsh abrasives or strong
chemical cleaners. A white buffing com-
pound can be used to restore the original
gloss to a scratched, dull, or faded area.
The finish of your boat should be thoroughly
cleaned, buffed, and polished at least once
each season. Take care when buffing or
polishing with a marine cleaner not to over-
heat the surface you are working, because
you will burn it.
A small outboard engine mounted on an
aluminum boat should be removed from the
boat and stored separately. Under all cir-
cumstances, any outboard engine must AL
WA YS be stored with the power head higher
than the lower unit and exhaust system.
This position will prevent water trapped in
the lower unit from draining back through
the exhaust ports into the power head.
Lower unit badly corroded because the zinc was not
replaced. Once the zinc is destroyed, more costly parts
will be damaged. Attention to the zinc condition is
extremely important during boat operation in salt
water.

1-2 SAFETY
A new zinc prior to installation. This inexpensive
item will save corrosion on more valuable parts.
Most outboard engines have a flat area
on the back side of the powerhead. When
the engine is placed with the flat area on
the power head and the lower unit resting on
the floor, the engine will be in the proper
altitude with the power head higher than the
lower unit.
1-3 CONTROLLING CORROSION
Since man first started out on the water,
corrosion on his craft has been his enemy.
The first form was merely rot in the wood
and then it was rust, followed by other
forms of destructive corrosion in the more
modern materials. One defense against cor-
rosion is to use similar metals throughout
the boat. Even though this is difficult to do
in designing a new boat, particularily the
undersides, similar metals should be used
whenever and wherever possible.
A second defense against corrosion is to
insulate dissimilar metals. This can be done
by using an exter ior coating of Sea Skin or
by insulating them with plastic or rubber
gaskets.
Using Zinc
The proper amount of zinc attached to a
boat is extremely important. The use of too
much zinc can cause wood burning by plac-
ing the metals close together and they be-
come hot . On the other hand, using too
DIAMETER
Diameter and pitch are the two basic dimensions of
a propeller. The diameter is measured across the
circumference of a circle scribed by the propeller
blades, as shown.
small a zinc plate will cause more rapid
deterioration of the metal you- are trying to
protect. If in doubt, consider the fact that
is is far better to replace the zincs than to
replace planking or other expensive metal
parts from having an excess of zinc.
When installing zinc plates, there are
two routes available. One is to install many
different zincs on all metal parts and thus
run the risk of wood burning. Another
route, is to use one large zinc on the tran-
som of the boat and then connect this zinc
to every underwater metal part through
internal bonding. Of the two choices, the
one zinc on the transom is the better way to
go.
Small outboard engines have a zinc plate
attached to the cavitation plate. Therefore,
the zinc remains with the engine at all
times.
1-4 PROPELLERS
As you know, the propeller is actually
what moves the boat through the water.
This is how it is done. The propeller oper-
ates in water in much the manner as a wood
screw does in wood. The propeller bites
into the water as it rotates. Water passes
between the blades and out to the rear in
the shape of a cone. The propeller biting
through the water in much the same manner
as a wood auger is what propels the boat.
Propeller and associated parts in order, washer,
shear-pin, and nut, ready for installation.

Arrangement of propeller and associated parts, in
order, for a small horsepower engine.
Diameter and Pitch
Only two dimensions of the propeller are
of real interest to the boat owner: the
diameter and the pitch. These two dimen-
sions are stamped on the propeller hub and
always appear in the same order: the diam-
eter first and then the pitch. For instance,
the number 15-19 stamped on the hub,
would mean the propeller had a diameter of
15 inches with a pitch of 19.
The diameter is the measured distance
from the tip of one blade to the tip of the
other as shown in the accompanying illus-
tration.
The pitch of a propeller is the angle at
which the blades are attached to the hub.
This figure is expressed in inches of water
travel for each revolution of the propeller.
In our example of a 15-19 propeller, the
propeller should travel 19 inches through the
water each time it revolves. If the propel-
ler action was perfect and there was no
slippage, then the pitch multiplied by the
propeller rpms would be the boat speed.
Most outboard manufacturers equip their
units with a standard propeller with a diam-
eter and pitch they consider to be best
suited to the engine and the boat. Such a
propeller allows the engine to run as near to
the rated rpm and horsepower (at full throt-
tle) as possible for the boat design.
The blade area of the propeller deter-
mines its load-carrying capacity. A two-
blade propeller is used for high-speed run-
ning under very light loads.
PROPELLERS 1-3
Shear-pin installed behind the propeller instead of in
front of the propeller.
A four-blade propeller is installed in
boats intended to operate at low speeds
under very heavy loads such as tugs, barges,
or large houseboats. The three-blade pro-
peller is the happy medium covering the
wide range between the high performahce
units and the load carrying workhorses.
Propeller Selection
There is no standard propeller that will
do the proper job in very many cases. The
list of sizes and weights of boats is almost
endless. This fact coupled with the many
boat-engine combinations makes the propel-
ler selection for a specific purpose a diffi-
cult job. In fact, in many cases the propel-
ler is changed after a few test runs. Proper
selection is aided through the use of charts
set up for various engines and boats. These
charts should be studied and understood
when buying a propeller. However, bear in
mind, the charts are based on average boats
10 ..
Diagram to explain the pitch dimension of a propeller. The pitch is the theoretical distance a propeller would travel
through the water if there was no slippage.

1 4 SAFETY
with average loads, therefore, it may be
necessary to make a change in size or pitch,
in order to obtain the desired results for the
hull design or load condition.
A wide range of pitch is available for
each of the larger horsepower engines. The
choice available for the smaller engines, up
to about 25 hp, is restricted to one or two
sizes. Remember, a low pitch takes a
smaller bite of the water than the high pitch
propeller. This means the low pitch propel-
ler will travel less distance through the
water per revolution. The low pitch will
require less horsepower and will allow the
engine to run faster and more efficiently.
It stands to reason, and it's true, that the
high pitch propeller will require more horse-
power, but will give faster boat speed if the
engine is allowed to tu rn to its rated rpm.
If a higher-pitched propeller is installed
on a boat, in an effort to get more speed,
extra horsepower will be required. If the
extra power is not available, the rpms will
be reduced to a less efficient level and the
actual boat speed will be less than if the
lower-pitched propeller had been left in-
stalled.
All engine manufacturers design their
units to operate with full throttle at, or
slightly above, the rated rpm. If you run
your engine at the rated rpm, you will
increase spark plug life, receive better fuel
economy, and obtain the best performance
CAVITATION BURN
o
Cavitation (air bubbles) formed at the propeller.
Manufacturers are constantly fighting this problem, as
explained in the text.
from your boat and engine. Therefore, take
time to make the proper propeller selection
for the rated rpm of your engine at full
throttle with what you consider to be an
average load. Your boat will then be cor-
rectly balanced between engine and pro-
peller throughout the entire speed range.
A reliable tachom eter must be used to
measure engine speed at full throttle to
ensure the engine will achieve full horse-
power and operate efficiently and safely.
To test for the correct propeller, make your
run in a body of smooth water with the
lower unit in forward gear at full throttle.
Observe the tachometer at full throttle.
NEVER run the engine at a high rpm when a
flush attachment is installed. If the reading
is above the manufacturer's recommended
operating range, you must try propellers of
greater pitch, until you find the one that
allows the engine to operate continually
within the recommended full throttle range.
If the engine is unable to deliver top
performance and you feel it is properly
tuned, then the propeller may not be to
blame. Operating conditions have a marked
effect on performance. For instance, an
engine will lose rpm when run in very cold
water. It will also lose rpm when run in salt
water as compared with fresh water. A hot,
low-barometer day will also cause your en-
gine to lose power.
Example of a damaged propeller. This unit should
have been replaced long before this amount of damage
was sustained.

Ventilation
Ventilation is the forming of voids in the
water just ahead of the propeller blades.
Marine propulsion designers are constantly
fighting the battle against the formation of
these voids due to excessive blade tip speed
and engine wear. The voids may be filled
with air or water vapor, or they may actual-
ly be a partial vacuum. Ventilation may be
caused by installing a piece of equipment
too close to the lower unit, such as the knot
indicator pickup, depth sounder, or bait tank
pickup.
Vibration
Your propeller should be checked reg-
ularly to be sure all blades are in good
condition. If any of the blades become bent
or nicked, this condition will set up vibra-
tions in the drive unit and the motor. If the
vibration becomes very serious it will cause
a loss of power, efficiency, and boat perfor-
mance. If the vibration is allowed to con-
tinue over a period of time it can have a
damaging effect on many of the operating
parts.
Vibration in boats can never be com-
pletely eliminated, but it can be reduced by
keeping all parts in good working condition
and through proper maintenance and lubr i-
cation. Vibration can also be reduced in
some cases by increasing the number of
blades. For this reason, many racers use
Rubber hub removed from a propeller. This hub was
removed because the hub was slipping in the propeller.
PROPELLERS 1-5
two-blade props and luxury cruisers have
four- and five-blade props installed.
Shock Absorbers
The shock absorber in the propeller plays
a very important role in protecting the
shafting, gears, and engine against the shock
of a blow, should the propeller strike an
underwater object. The shock absorber al-
lows the propeller to stop rotating at the
instant of impact while the power train
continues turning.
How much impact the propeller is able
to withstand before causing the clutch hub
to slip is calculated to be more than the
force needed to propel the boat, but less
than the amount that could damage any part
of the power train. Under normal propulsion
loads of moving the boat through the water,
the hub will not slip. However, it will slip if
the propeller strikes an object with a force
that would be great enough to stop any part
of the power train.
I
~~ - 0
0
RAKE
illustration depicting the rake of a propeller, as
explained in the text.

1-6 SAFETY
If the power train was to absorb an
impact great enough to stop rotation, even
for an instant, something would have to give
and be damaged. If a propeller is subjected
to repeated striking of underwater objects,
it would eventually slip on its clutch hub
under normal loads. If the propeller would
start to slip, a new hub and shock absorber
would have to be installed.
Propeller Rake ,
If a propeller blade is examined on a cut
extending directly through the center of the
hub, and if the blade is set vertical to the
propeller hub, as shown in the accompanying
illustration, the propeller is said to have a
zero degree (00) rake. As the blade slants
back, the rake increases. Standard propel-
o 0
lers have a rake angle from a to 15 •
A higher rake angle generally improves
propeller performance in a cavitating or
ventilating situation. On lighter, faster
boats, higher rake often will increase per-
formance by holding the bow of the boat
higher.
Progressive Pitch
Progressive pitch is a blade design inno-
vation that improves performance when for-
ward and rotational speed is high and/or the
propeller breaks the surface of the water.
Progressive pitch starts low at the lead-
ing edge and progressively increases to the
trailing edge, as shown in ,the accompanying
illustration. The average pitch over the
entire blade is the number assigned to that
propeller. In the illustration of the progres-
sive pitch, the average pitch assigned to the
propeller would be 21.
CONSTANT PITCH
Propeller with a cupped leading edge. Cupping
gives the propeller a better hold in the water.
Cupping
If the propeller is cast with a edge curl
inward on the trailing edge, the blade is said
to have a cup. In most cases, cupped blades
improve performance. The cup helps the
blades to HOLD and not break loose, when
operating in a cavitating or ventilating situ-
ation. This action permits the engine to be
trimmed out further, or to be mounted high-
er on the transom. This is especially true on
high-performance boats. Either of these
two adjustments will usually add to higher
speed.
PROGRESSIVE PITCH
Comparison of a constant and progressive pitch propeller. Notice how the pitch of the progressive pitch propeller,
right, changes to give the blade more thrust and therefore, the boat more speed.

The cup has the effect of adding to the
propeller pitch. Cupping usually will reduce
full-throttle engine speed about 150 to 300
rpm below the same pitch propeller without
a cup to the blade. A propeller repair shop
is able to increase or decrease the cup on
the blades. This change, as explained, will
al ter engine rpm to meet specific operating
demands. Cups are rapidly becoming
standard on propellers.
in order for a cup to be the most effec-
tive, the cup should be completely concave
(hollowed) and finished with a sharp corner.
If the cup has any convex rounding, the
effectiveness of the cup will be reduced.
Rotation
Propellers are manufactured as right-
hand rotation (RH), and as left-hand rota-
tion (LH). The standard propeller for out-
boards is RH rotation.
A right-hand propeller can easily be
identified by observing it as shown in the
accompanying illustration. Observe how the
blade slants from the lower left toward the
upper right. The left-hand propeller slants
in the opposite direction, from upper left to
lower right, as shown.
When the propeller is observed rotating
from astern the boat, it will be rotating
clockwise when the engine is in forward
gear. The left-hand propeller will rotate
counterclockwise.
1-5 FUEL SYSTEM
With Built-in Fuel Tank
All parts of the fuel system should be
selected and installed to provide maximum
COUNTERCLOCKWISE
OR
LEFT HAND
CLOCKWISE
OR
RIGHT HAND
Right- and left-hand propellers shOWing how the
angle of the blades is reversed. Right-hand propellers
are by far the most popular;
PROPELLERS 1-7
service and protection against leakage. Re-
inforced flexible sections should be installed
in fuel lines where there is a lot of motion,
such as at the engine connection. The
flaring of copper tubing should be annealed
after it is formed as a protection against
hardening. CAUTION: Compression fittings
should NOT be used because they are so
easily overtightened, which places them un-
der a strain and subjects them to fatigue.
Such conditions will cause the fitting to leak
after it is connected a second time.
The capacity of the fuel filter must be
large enough to handle the demands of the
engine as specified by the engine manufac-
turer.
A manually-operated valve should be in-
stalled if anti-siphon protection is not pro-
vided. This valve should be installed in the
fuel line as close to the gas tank as possible.
Such a valve will maintain anti-siphon pro-
tection between the tank and the engine.
Fuel tanks should be mounted in dry,
well ventilated places. Ideally, the fuel
tanks should be installed above the cockpit
floors, where any leakage will be quickly
detected. In order to obtain maximum cir-
culation of air around fuel tanks, the tank
should not come in contact with the boat
hull except through the necessary supports.
The supporting surfaces and hold-downs
must fasten the tank firmly and they should
be insulated from the tank surfaces. This
insulation material should be non-abrasive
and non-absorbent material. Fuel tanks
installed in the forward portion of the boat
should be especially well secured and pro-
tected because shock loads in this area can
be as high as 20 to 25 g's,
A three-position valve permits fuel to be drawn
from either tank or to be shut off completely. Such an
arrangement prevents accidental siphoning of fuel from
the tank.

1-8 SAFETY
Taking On Fuel
The fuel tank of your boat should be kept
full to prevent water from entering the
system through condensation caused by tem-
perature changes. Water droplets forming is
one of the greatest enemies of the fuel
system. By keeping the tank full, the air
space in the tank is kept to an absolute
minimum and there is no room for moisture
to form. It is a good practice not to store
fuel in the tank over an extended period, say
for six months. Today, fuels contain ingre-
dients that change into gums when stored
for any length of time. These gums and
varnish products will cause carburetor prob-
lems and poor spark plug performance. An
additive (Sta-Bil) is available and can be
used to prevent gums and varnish from
forming.
Static Electricity
In very simple terms, static electricity is
called fr icti onal electr ici ty. It is generated
by two dissimilar materials moving over
each other. One form is gasoline flowing
through a pipe or into the air. Another form
is when you brush your hair or walk across a
synthetic carpet and then touch a metal
object. All of these actions cause an elec-
trical charge. In most cases, static electri-
city is generated during very dry weather
conditions, but when you are filling the fuel
tank on your boat it can happen at any time.
Fuel Tank Grounding
One area of protection against the build-
up of static electricity is to have the fuel
An OMC fuel tank equipped with a quick-disconnect
fitting. This type of arrangement is handy when the
tank must be removed from the boat to obtain fuel.
Old style pressure-type tank showing the fuel line to
the engine and quick-disconnect fitting.
tank properly grounded (also known as bond-
ing). A direct metal-to-metal contact from
the fuel hose nozzle to the water in which
the boat is floating. If the fill pipe is made
of metal, and the fuel nozzle makes a good
contact with the deck plate, then a good
ground is made.
As an economy measure, some boats use
rubber or plastic filler pipes because of
compound bends in the pipe. Such a fill line
does not give any kind of ground and if your
boat has this type of installation and you do
Adding fuel to a six-gallon OMC fuel tank. Some
fuel must be in the tank before oil is added to prevent
the oil from accumulating on the tank bottom.

not want to replace the filler pipe with a
metal one, then it is possible to connect the
deck fitting to the tank with a copper wire.
The wire should be 8 gauge or larger.
The fuel line from the tank to the engine
should provide a continuous metal-to-metal
contact for proper grounding. If any part of
this line is plastic or other non-metallic
material, then a copper wire must be con-
nected to bridge the non-metal material.
The power train provides a ground through
the engine and drive shaft, to the propeller
in the water.
Fiberglass fuel tanks pose problems of
their own. One method of grounding is to
run a copper wire around the tank from the
fill pipe to the fuel line. However, such a
wire does not ground the fuel in the tank.
Manufacturers should imbed a wire in the
fiberglass and it should be connected to the
intake and the outlet fittings. This wire
would avoid corrosion which could occur if a
wire passed through the fuel. CAUTION: It
is not advisable to use a fiberglass fuel tank
if a grounding wire was not installed.
Anything you can feel as a shock is
enough to set off an explosion. Did you
know that under certain atmospheric con-
ditions you can cause a static explosion
yourself, particularly if you are wearing
synthetic clothing. It is almost a certainty
you could cause a static spark if you are
NOT wearing insulated rubber-soled shoes.
As soon as the deck fitting is opened,
fumes are released to the air. Therefore, to
be safe you should ground yourself before
A fuel tank properly grounded to prevent static
electricity. Static electricity could be extremely dan-
gerous when taking on fuel.
LOADING 1-9
opening the fill pipe deck fitting. One way
to ground yourself is to dip your hand in the
water overside to discharge the electricity
in your body before opening the filler cap.
Another method is to touch the engine block
or any metal fitting on the dock which goes
down into the water.
1-6 LOADING
In order to receive maximum enjoyment,
with safety and performance, from your
boa t, take care not to exceed the load
capacity given by the manufacturer. A
plate attached to the hull indicates the U.S.
Coast Guard capacity information in pounds
for persons and gear. If the plate states the
maximum person capacity to be 750 pounds
and you assume each person to weigh an
average of 150 lbs., then the boat could
carry five persons safely. If you add anoth-
er 250 lbs. for motor and gear, and the
maximum weight capacity for persons and
gear is 1,000 Ibs. or more, then the five
persons and gear would be within the limit.
Try to load the boat evenly port and
starboard. If you place more weight on one
side than on the other, the boat will list to
the heavy side and make steering difficult.
You will also get better performance by
placing heavy supplies aft of the center to
keep the bow light for more efficient plan-
ing.
••
u.s. COAST GUARD
MAXIMUM CAPACITIES
PERSONS OR
LBS
LBS PERSONS,MOTOR,GEAR
H.P. MOTOR
u.s. Coast Guard plate affixed to all new boats.
Whenthe blanks are filled in, the plate will indicate the
Coast Guard's recommendations for persons, gear, and
horsepower to ensuresafe operation of the boat. These
recommendations should not be exceeded, as explained
in the text.

1-10 SAFETY
C Jar ifica tion
Much confusion arises from the terms,
certification, requirements, approval, regu-
lations, etc. Perhaps the following may
clarify a couple of these points.
1- The Coast Guard does not approve
boats in the same manner as they Approve
life jackets. The Coast Guard applies a
formula to inform the public of what is safe
for a particular craft.
2- If a boat has to meet a particular
regulation, it must have a Coast Guard
certification plate. The public has been led
to believe this indicates approval of the
Coast Guard. Not so.
3- The certification plate means a will-
ingness of the manufacturer to meet the
Coast Guard regulations for that particular
craft. The manufacturer may recall a boat
if it fails to meet the Coast Guard require-
ments.
4- The Coast Guard certification plate,
see accompanying illustration, mayor may
not be metal. The plate is a regulation for
the manufacturer. It is only a warning plate
and the public does not have to adhere to
the restrictions set forth on it. Again, the
pla te sets forth information as to the Coast
Guard's opinion for safety on that particular
boat.
Type I PFD Coast Guard approved life jacket. This
type flotation device provides the greatest amount of
buoyancy. NEVER use them for cushions or other
purposes.
5- Coast Guard Approved equipment is
equipment which has been approved by the
Commandant of the U.S. Coast Guard and
has been determined to be in compliance
with Coast Guard specif ica tions and regula-
tions relating to the materials, construction,
and performance of such equipment.
1-7 HORSEPOWER
The maximum horsepower engine for
each individual boat should not be increased
by any great amount without checking re-
quirements from the Coast Guard in your
area. The Coast Guard determines horse-
power requirements based on the length,
beam, and depth of the hull. TAKE CARE
NOT to exceed the maximum horsepower
listed on the plate or the warranty and
possibly the insurance on the boat may be-
come void.
1-8 FLOTATION
If your boat is less than 20 ft. overall, a
Coast Guard or BIA (Boating Industry of
America) now changed to NMMA (National
Marine Manufacturers Association) require-
ment is that the boat must have buoyant
material built into the hull (usually foam) to
keep it from sinking if it should become
swamped. Coast Guard requirements are
mandatory but the NMMA is voluntary.
Kept from sinking is defined as the
ability of the flotation material to keep the
boat from sinking when filled with water
A Type N PFD cushion device intended to be thrown
to a person in the water. If air can be squeezed out ot
the cushion it is no longer fit for service as a PFD.

and with passengers clinging to the hull.
One restriction is that the total weight of
the motor, passengers, and equipment
aboard does not exceed the maximum load
capacity listed on the plate.
Life Preservers -Personal Flotation Devices
(PFDs)
The Coast Guard requires at least one
Coast Guard approved life-saving device be
carried on board all motorboats for each
person on board. Devices approved are
identified by a tag indicating Coast Guard
approval. Such devices may be life preserv-
ers, buoyant vests, ring buoys, or buoyant
cushions. Cushions used for seating are
serviceable if air cannot be squeezed out of
it. Once air is released when the cushion is
squee zed, it is no longer fit as a flota tion
device. New foam cushions dipped in a
rubberized material are almost indestruct-
ible.
Life preservers have been classified by the
U.S. Coast Guard into five distinct categories.
PFDs presently acceptable on recreational boats
fall into one of these five designations. AllPFDs
MUST be U.S. Coast Guard approved, in good
and serviceable condition, and ofan appropriate
size for the persons who intend to wear them.
Wearable PFDs MUST be readily accessibleand
throwable devices MUST be immediately avail-
able for use.
Type I PFD has the greatest required
buoyancy and is designed to turn most
UNCONSCIOUS persons in the water from a
face down position to a vertical or slightly
backward posi tion, The adul t size device
provides a minimum buoyancy of 22 pounds
and the child size provides a minimum buoy-
ancyof 11 pounds. The Type I PFD provides
the greatest protection to its wearer and is
most effective for all waters and conditions.
Type II PFD is designed to turn its wear-
er in a vertical or slightly backward position
in the water. The turning action is not as
pronounced as with a Type I. The device
will not turn as many different type persons
under the same conditions as the Type I. An
adul t size device provides a minimum buoy-
ancy of 15Y2 pounds, the medium child size
provides a minimum of 11 pounds, and the
infant and small child sizes provide a min-
imum buoyancy of 7 pounds.
FLOTATION I-II
Type III PFD is designed to permit the
wearer to place himself (herself) in a
vertical or slightly backward position. The
Type III device has the same buoyancy as
the Type II PFD but it has little or no
turning ability. Many of the Type III PFD
are designed to be particularly useful when
water skiing, sailing, hunting, fishing, or en-
gaging in other water sports. Several of this
type will also provide increased hypothermia
protection.
Type IV PFD is designed to be thrown to
a person in the water and grasped and held
by the user until rescued. It is NOT design-
ed to be worn. The most common Type IV
PFD is a ring buoy or a buoyant cushion.
Type V PFD is any PFD approved for
restricted use.
Coast Guard regulations state, in general
terms, that on all boats less than 16 ft.
overall, one Type I, II, III, or IV device shall
be carried on board for each person in the
boat. On boats over 26 f t., one Type I, II, or
III device shall be carried on board for each
person in the boat plus one Type IV device.
It is an accepted fact that most boating
people own life preservers, but too few
actually wear them. There is little or no
excuse for not wearing one because the
modern comfortable designs available today
do not subtract from an individual's boating
pleasure. Make a life jacket available to
Type IV PFD ring buoy designed to be thrown. On
ocean cruisers, this type device usually has a weighted
pole with flag, attached to the buoy.

1-12 SAFETY
your crew and advise each member to wear
it. If you are a crew member ask your
skipper to issue you one, especially when
boating in rough weather, cold water, or
when running at high speed. Naturally, a
life jacket should be a must for non-swim-
mers any time they are out on the water in
a boat.
1-9 EMERGENCY EQUIPMENT
Visual Distress Signals
The Regulation
Since January 1, 1981, Coast Guard Reg-
ulations require all recreation boats when
used on coastal waters, which includes the
Great Lakes, the territorial seas and those
waters directly connected to the Great
Lakes and the territorial seas, up to a point
where the waters are less than two miles
wide, and boats owned in the United States
when operating on the high seas to be equip-
ped with visual distress signals.
Internationally accepted distress signals.
The only exceptions are during daytime
(sunrise to sunset) for:
Recrea tional boats less than 16 ft. (5
meters) in length.
Boats participating in organized events
such as races, regattas or marine parades.
Open sailboats not equipped with propul-
sion machinery and less than 26 ft. (8 me-
ters) in length.
Manually propelled boats.
The above listed boats need to carry
night signals when used on these waters at
night.
Pyrotechnic visual distress signaling de-
vices MUST be Coast Guard Approved, in
serviceable condition and stowed to be read-
ily accessible. If they are marked with a
date showing the serviceable life, this date
must not have passed. Launchers, produced
before Jan. 1, 1981, intended for use with
approved signals are not required to be
Coast Guard Approved.
USCG Approved pyrotechnic visual dis-
tress signals and associated devices include:
Pyrotechnic red flares, hand held or aer-
ial. Pyrotechnic orange smoke, hand held or
floating.
Launchers for aerial red meteors or par-
achute flares.
Moisture-protected flares should be carried on board
for use as a distress signal.

None-pyrotechnic visual distress signal-
ing devices must carry the manufacturer's
certification that they meet Coast Guard
requirements. They must be in serviceable
condition and stowed so as to be readily
accessible.
This group includes:
Orange distress flag at least 3 x 3 feet
with a black square and ball on an orange
background.
Electric distress light -- not a flashlight
but an approved electric distress light which
MUST automatically flash the international
SOS distress signal (.•• - - -. ..) four to six
times each minute.
Types and Quantities
The following variety and combination of
devices may be carried in order to meet the
requirements.
1- Three hand-held red flares (day and
night).
2- One electric distress light (night on-
ly).
3- One hand-held red flare and two par-
achute flares (day and night).
4- One hand-held orange smoke signal,
two floating orange smoke signals (day) and
one electric distress light (day and night).
If young children are frequently aboard
your boat, careful selection and proper sto-
wage of visual distress signals becomes es-
pecially important. If you elect to carry
pyrotechnic devices, you should select those
in tough packaging and not easy to ignite
should the devices fall into the hands of
children.
Coast Guard Approved pyrotechnic de-
vices carry an expiration date. .This date
can NOT exceed 42 months from the date of
An adequately stocked first-aid kit should be on
board for the safety of crew and guests.
COMPASS 1-13
manufacture and at such time the device
can no longer be counted toward the min-
imum requirements.
SPECIAL WORDS
In some states the launchers for meteors
and parachute flares may be considered a
firearm. Therefore, check with your state
authorities before acquiring such a launcher.
First Aid Kits
The first-aid kit is similar to an insur-
ance policy or life jacket. You hope you
don't have to use it but if needed, you want
it there. It is only natural to overlook this
essential item because, let's face it, who
likes to think of unpleasantness when plan-
ning to have only a good time. However,
the prudent skipper is prepared ahead of
time, and is thus able to handle the emer-
gency without a lot of fuss.
Good commercial first-aid kits are avail-
able such as the Johnson and Johnson Ma-
rine First-Aid Kit . With a very modest
expenditure, a well-stocked and adequate
kit can be prepared at home.
Any kit should include instruments, sup-
plies, and a set of instructions for their use.
Instruments should be protected in a water-
tight case and should include: scissors,
tweezers, tourniquet, thermometer, safety
A sounding device should mounted close to the
helmsman for use in sounding an emergency alarm.

1-14 SAFETY
pins, eye-washing cup, and a hot water bot-
tle. The supplies in the kit should include:
assorted bandages in addition to the various
sizes of band-aids , adhesive tape, absorb-
ent cotton, applicators, petroleum jelly, an-
tiseptic (liquid and ointment), local oint-
ment, aspirin, eye ointment, antihistamine,
ammonia inhalent, sea-sickness pills, ant-
acid pills, and a laxative. You may want to
consult your family physician about includ-
ing antibiotics. Be sure your kit contains a
first-aid manual because even though you
have taken the Red Cross course, you may
be the patient and have to rely on an
untrained crew for care.
Fire Extinguishers
All fire extinguishers must bear Under-
writers Laboratory (UL) Marine Type ap-
proved labels. With the UL certification,
the extinguisher does not have to have a
Coast Guard approval number. The Coast
Guard classifies fire extinguishers according
to their size and type.
Type B-1or B-II Designed for extinguishing
flammable liquids. This type extinguisher is
required on all motorboats.
The Coast Guard considers a boat having
one or more of the following conditions as a
boat of closed construction subject to fire
extinguisher regulations.
A suitable fire extinguisher should be mounted close
to the helmsman for emergency use.
1- Inboard engine or engines.
2- Closed compartments under thwarts
and seats wherein portable fuel tanks may
be stored.
3- Double bottoms not sealed to the hull
or which are not completely filled with
flotation materials.
4- Closed living spaces.
5- Closed stowage compartments in
which combustible or flammable material is
stored.
6- Permanently installed fuel tanks.
Detailed classification of fire extingui-
shers is by agent and size:
B-1contains 1-1/4gallons foam, or 4 pounds
carbon dioxide, or 2 pounds dry chemical
agent, or 2-1/2 pounds Halon.
B-II contains 2-1/2 gallons foam, or 15
pounds carbo dioxide, or 10pounds dry chemi-
cal agent, or 10 pounds Halon.
The class of motorboat dictates how
many fire extinguishers are required on
board. One B-II unit can be substituted for
two B-1 extinguishers. When the engine
compartment of a motorboat is equipped
with a fixed (bull t-in) extinguishing system,
one less portable B-1 unit is required.
Dry chemical fire extinguishers without
At least one gallon of emergency fuel should be kept
on board in an approved container.

gauges or indicating devices must be weigh-
ed and tagged every 6 months. If the gross
weight of a carbon dioxide (CO?) fire extin-
guisher is reduced by more than 10% of the
net weight, the extinguisher is not accept-
able and must be recharged.
READ labels on fire extinguishers. If the
extinguisher is U.L. listed, it is approved for
marine use.
DOUBLE the number of fire extinguish-
ers recommended by the Coast Guard, be-
cause their requirements are a bare MINI-
MUM for safe operation. Your boat, family,
and crew, must certainly be worth much
more than bare minimum .
1 10 COMPASS
Selection
The safety of the boat and her crew may
depend on her compass. In many areas
wea ther conditions can change so rapidly
that within minutes a skipper may find him-
self socked-in by a fog bank, a rain squall,
or just poor visibility. Under these condi-
tions, he may have no other means of keep-
ing to his desired course except with the
compass. When crossing an open body of
water, his compass may be the only means
of making an accurate landfall.
During thick weather when you can nei-
ther see nor hear the expected aids to
navigation, attempting to run out the time
on a given course can disrupt the pleasure of
the cruise. The skipper gains little comfort
in a chain of soundings that does not match
those given on the chart for the expected
area. Any stranding, even for a short time,
can be an unnerving experience.
A pilot will not knowingly accept a
cheap parachute. A good boater should not
accept a bargain in lifejackets, fire ex-
tinguishers, or compass. Take the time and
spend the few extra dollars to purchase a
compass to fit your expected needs. Re-
gardless of what the salesman may tell you,
postpone buying until you have had the
chance to check more than one make and
model.
Lift each compass, til t and turn it, sim-
ulating expected motions of the boat. The
compass card should have a smooth and
stable reaction.
The card of a good quality compass will
come to rest without oscillations about the
lubber's line. Reasonable movement in your
hand, comparable to the rolling and pitching
MISCELLANEOUS EQUIPMENT 1 15
The compass is a delicate instrument and deserves
respect. It should be mounted securely and in position
where it can be easily observed by the helmsman.
of the boat, should not materially affect the
reading.
Installation
Proper installation of the compass does
not happen by accident. Make a critical
check of the proposed location to be sure
compass placement will permit the helms-
man to use it with comfort and accuracy.
First, the compass should be placed directly
in front of the helmsman and in such a
position that it can be viewed without body
stress as he sits or stands in a posture of
relaxed alertness. The compass should be in
the helmsman's zone of comfort. If the
compass is too far away, he may have to
bend forward to watch it; too close and he
must rear backward for relief.
Do not hesitate to spend a few extra dollars for a
good reliable compass. If in doubt, seek advice from
fellOW boaters.