Small Boats Flashcards
Which number is used to determine the service manual required
Model/product number
Outboard engines are labeled with
A serial number and a model/product number
Sequentially ordered number issued by the manufacturer to track outboard engine production
Serial number
Provides the information necessary to properly maintain and service the outboard engine
Manufacturers service manual
Precautions that must be kept in mind whenever working on an outboard engine
General safety warnings
Indicates a strong possibility of severe personal injury or death if instructions are not followed
Warning
Indicates a possibility of personal injury or equipment damage if instructions are not followed
Caution
Gives helpful information
Note
Seven pieces of information normally contained within a service manual
Index of topics, engine specs, torque specs, safety precautions and warnings, procedures for servicing the outboard, troubleshooting procedures, drawings and schematics
Means the engine burns fuel
Combustion
Means the fuel is burned inside the engine
Internal combustion
Creates a seal between the piston and cylinder wall
Metal rings
Attached to the crankshaft and balances the crankshaft by offsetting the weight of the piston and connecting rod
Counterweight
Heavily weighted wheel attached to one end of the crankshaft, the momentum keeps the crankshaft, connecting rod, and piston moving until the cylinder fires again
Flywheel
As the piston is pulled down during the intake stroke, a fresh charge of air/fuel mixture is drawn into the cylinder
Intake
The piston now begins to move upward and starts to compress the air/fuel mixture in the cylinder
Compression
The fuel air mixture ignites and burns very rapidly. Increases in pressure generated by combustion force the piston downward in the cylinder
Power
Upon completion of the power stroke, the piston starts to move upward again. The continuing upward movement forces the hot, burned gases out. Once the piston reaches the top, it starts to go back down and the cycle repeats
Exhaust
Uses reed valves opened and closed by pressure differences
Carbureted two stroke engine
Uses a camshaft driven by, and precisely timed to the crankshaft to mechanically open and close tappet valves via push rods and rocker arms
Four stroke engine
This engine is fuel injected, and provides better efficiency and reduced emissions
Four stroke engine
Develops significant torque at low RPMs
Four stroke engine
Lacks burst of power experienced with the other engine
Four stroke engine
Most outboard engines are
Two stroke
Rotating shaft driven by a crank and turned by a piston moving up and down in a cylinder, that changes the linear motion of the piston to rotary motion
Crankshaft
Metal casting containing the cylinders and cooling ducts of an engine
Cylinder block
Housing for the crankshaft with one side bolted to the cylinder block and the other side bolted to the intake manifold
Crankcase
Detachable plate bolted to the cylinder block containing part of the combustion chamber and the valves, spark plugs, and fuel injectors
Cylinder head
Network of passages that directs air to the cylinders
Intake manifold
Part of the two stroke engine that controls the intake of air into the crankcase
Leaf plate assembly (reed valves)
Changing pressures in the crankcase actuate this valve
Reed valve
Hole machined into the cylinder wall of a two stroke engine through which spent combustion gases exit. Piston movement opens and closes the port
Exhaust port
Pressurized air rushes into the cylinder forcing any remaining gases out the exhaust ports
Scavenging
Type of engine used on majority of coast guard small boats
Four stroke outboard
Engine oil is changed and recycled instead of being burned in the cylinders
Wet type sump
Additional parts of a four stroke engine
Camshaft, cam lobes, intake valve, exhaust valve, rocker arm
Cylindrical rod with protruding cam lobes that control the opening and closing of the intake and exhaust valves, and on some models the fuel injector pumps
Camshaft
Oblong eccentric projections on the camshaft that push against the rocker arms to open the valves as the camshaft rotates
Cam lobes
The part of the actuating assembly that admits air/fuel mixture into the cylinder
Intake valve
The part of the actuating assembly that opens to allow the discharge of exhaust gases from the cylinder
Exhaust valve
Transmits the motion of the cam to the valve, one end is in contact with the valve stem, and the camshaft actuates the other end
Rocker arm
Has a wet type oil sump with a filter that requires maintenance
Four stroke
Has a pulley on the end of the crankshaft to drive the cam belt
Four stroke
Has a camshaft which actuates the tappet valves
Four stroke
Has a rocker lever assembly to open and close the tappet valves
Four stroke
Burns its oil in combustion
Two stroke
May or may not have a cam
Two stroke
Uses reed valves and exhaust ports
Two stroke
Sides of the piston act like valves, covering and uncovering the intake and exhaust ports
Two stroke
On the compression stroke the fuel/air mixture is compressed approximately
One-ninth its original volume
Require special lubricating oil to be mixed with the gasoline for proper lubrication
Two stroke engines
Unleaded gasoline can have how much ethanol
10% ethanol by volume
Unleaded gasoline can have how much methanol
5% methanol by volume
Only authorized source of information for repairs and maintenance to outboard engines fuel system
Manufacturers service manual
Two types of fuel tanks
Built in, portable
Filler tube and cap accessible to the operator
Built in tank
Vented to relieve the vacuum created by the fuel pump and pressure created by filling the tank
Built in tank
Installed level indicating float gauges that send a signal to a gas gauge on the console
Built in tank
Average portable tank holds how many gallons
6
Portable tanks are usually constructed of
Plastic
Has a filler cap with a vacuum vent
Portable tank
Has a fuel pickup tube with a strainer at the end, mounted inside the tank
Portable tank
Has a quick disconnect fitting to connect the outboards fuel supply hose
Portable tank
Has a float type level indicator
Portable tank
Must be USCG-approved type A1 or B1 fuel hose
Built in
Has an inline primer squeeze bulb which incorporates a one way check valve
Built in
Attachments via hose clamps or quick disconnect fittings
Built in
Fuel hoses ordered as complete units
Portable tanks
Utilize quick disconnect fittings with built in check valves at both ends of the hose
Portable tanks
Fuel hoses must be of what type to prevent damage from ethanol based fuels
Alcohol resistant type
Replace fuel hose at the first sign of
Damage, deterioration, or hardness
Generally boats with installed tanks have the following components
Mesh strainer on the pickup tube in the tank, bulkhead mounted fuel filter and/or water separator, secondary inline filter
Connected to the crankcase by a short hose or passage, and are operated by alternating pressure and vacuum pulses from the crankcase
Two stroke outboard fuel pumps
What kind of fuel pump does a four stroke outboard use
Mechanically driven diaphragm fuel pump
Supplies the engine with the correct air/fuel mixture and adjusts the amount of air/fuel mixture as necessary to accommodate various operating speeds and loads
Carburetor
To operate efficiently, the engine needs about ____ units of air for a single unit of fuel measured by ____
12, weight
Atomize the fuel prior to combustion by actively injecting fuel into the combustion chamber or intake manifold at an appropriate point in the piston cycle
Fuel injection system
Force the fuel through nozzles under pressure rather than using the force of air rushing through
Fuel injector
Fuel being mixed with air is more precisely controlled, and the mixture is more evenly atomized for engine load in this system
Fuel injection
Two types of fuel injection
Direct injection, indirect injection
Use an injector mounted on the cylinder head which delivers fuel under pressure directly into the combustion chamber
Direct injection system
Uses a fuel injector that is located on the intake manifold
Indirect ignition system
Uses smaller injections of lighter material and starts the atomization process of fuel and air outside of the combustion chamber
Indirect ignition system
Removes water from the fuel prior to the fuel filter
Water separator
Removes particulate debris from the fuel system
Fuel filter
Transfers fuel from the fuel tank to the vapor separator
Low pressure pump
Removes fuel vapors prior to the high pressure fuel pumps fuel supply to prevent damage to the pump
Vapor separator
Ensures proper operation of the fuel system, may also cool fuel returning from the fuel rail
Vapor separator
Supplies pressurized fuel to the fuel rail, cleans the fuel prior to it entering the injectors
High pressure fuel pump
Supplies pressurized fuel for the injectors
Fuel rail
Maintains a consistent pressure of fuel in the fuel rail
Pressure regulator
With a fuel injector, causes the armature to move upward
Pressure in the fuel system or the signal from the engine control module
Must regulate the amount of air entering the engine to maintain the correct mixture of air and fuel
Fuel injected engine
Uses a throttle body to regulate air flow
Air induction system
Butterfly valve which allows a predetermined amount of air into the engine based upon the throttle input
Throttle body
May be controlled by direct cable or the position may be monitored and controlled by the ECM
Throttle body
ECM
Engine control module
Device that allows a small amount of air into the engine when the engine is idling and the throttle is closed
Idle air control (IAC)
Uses a pump to draw oil from a reservoir, which is delivered to an oil injector
Oil injection system
Delivers a precise amount of oil to the inlet side of each cylinder
Oil injector
Delivers oil under pressure to an oil manifold which distributes the oil to the crankshaft bearings and other internal moving parts
Oil injector
Oil injection system is controlled by
The engines electronic control system
IAC
Idle air control
OIS
Oil injection system
Accompanies outboards equipped with an oil injection system (OIS)
Oil reservoir
When the oil level in the tank is below ____ , the contact washer makes an electrical connection between the contact clips
One fourth full
The warning horn for low oil sounds a tone every ____
20 - 40 seconds
Oil injection pump and manifold assembly consist of the following components
Oil injector pump, oil distribution manifold, pickup tube and filter, low oil sending unit, oil pressure switch
Incorporate most of the working parts of the oil reservoir
Oil injection pump and manifold assembly
What does the oil pass through on its way to the cylinders
Oil tank, oil inlet filter, oil pickup, oil injection pump, oil distribution manifold, oil distribution hose
Connect the intake port areas of the cylinders to circulate residual oil back to the block
Internal powerhead oil drain passages
Used to recirculate any accumulation of oil from various locations in the powerhed
External hoses and fittings, internal cylinder/crankcase passages, and intake manifold passages
Provided through internal powerhead oil drain passages, external fittings, and external inline check valves and hoses
Movement of oil through the upper, center, and lower main bearing
Work together to flow cooling water throughout an engine and keep the outboard engine running at a relatively cool but constant temperature
Cooling system components
Pushes the water into the pickup tube
Water pump
Located in the gearcase under the water pump
Water intake screen
Runs the length of the mid-section, carries the water into the exhaust manifold
Pickup tube
Allow the flow of cooling water around each of the cylinders
Cylinder block water jacket
Opens and allows passage through the cylinder head water jackets
Temperature regulator or thermostat
Carries the exiting engine exhaust and water to the propeller hub
Exhaust manifold
Passes the exiting water and engine exhaust out of the engine
Propeller hub
Located on the side of the gearcase, allow cooling water to enter the engine
Water intake holes
First component that water passes in the cooling system
Water intake holes
Plastic strainer basket located in the gearcase under the water pump, filters debris from the water before the cooling water enters the engine
Water intake screen
Supplies cooling water throughout the engine, driven by main driveshaft
Water pump
Have cast in double walls known as water jackets, permits passage of cooling water around the walls
Cylinder block and cylinder head
To keep cooling surfaces clean if marine growth and salt build up, the engine must be
Flushed with freshwater immediately after use in salt water or brackish water
At idle the thermostat will
Unseat to allow some cooling water flow
Works with the thermostat to cool the engine
Pressure sensing device
Provides the onboard computer with the coolant temperature information for fuel and ignition optimization
Engine coolant temperature sensor
Most temperature sensors are
Temperature dependent resistors
The resistance of the sensor _____ as the temperature increases
Decreases
High temperatures provide _____ voltage
Low signal
All temperature sensors have the same
Response curve
Bolted through the bottom of the mid-section, and is the power transmission portion of the outboard
Gearcase
Its function is to transmit the engine’s power to the propeller
Gearcase
Moves the boat in forward or reverse
Propeller
Typical gear ratio of an outboard gearcase ranges from
1.87:1 to 2.4:1
Five main components of the gearcase
Reverse gear, pinion gear, clutch shifter, forward gear, shift mechanism
Splined to the crankshaft in the powerhead and turns at engine speed. Extends vertically down through the mid-section, and ends in the gearcase, just shy of the horizontal propeller shaft
Driveshaft
Pressed onto the bottom of the driveshaft, it is in constant mesh with the reverse and forward gears, and turns each one in opposite directions any time the engine is rotated
Pinion gear
The driveshaft is supported by
Two sets of bearings, an upper and a lower
Pressed into a housing that bolts to the top of the gearcase. This housing can be seen when the water pump is removed from the gearcase
Upper bearing
Upper gear housing also houses
Thrust bearing, thrust washer, and the shims
Used to adjust the height of the driveshaft and pinion gear
Shims
Height of the driveshaft and pinion gear is critical because
Controls the amount of mesh/contact between the pinion gear and the forward and reverse gears
Pressed into the gearcase housing at the bottom of the driveshaft
Lower bearing
Are in constant mesh with the pinion gear and are each turned in opposite directions any time the engine is rotated or running
Forward and reverse gears
Directly move the propeller shaft
Clutch shifter
Three things housed in the forward area of the gearcase
Forward gear, thrust bearing, thrust washer
When placed in the forward direction, the clutch shifter is moved into contact with and turned by the
Forward gear
When placed in the reverse direction, the clutch shifter is moved into contact with and turned by the
Reverse gear
Three things housed in the propeller shaft holder
Reverse gear, thrust bearing, and thrust washer
The propeller shaft holder contains ____ that retain the gearcase oil and prevent water from entering
O-rings and seals
Housed horizontally in the lower gearcase, it uses the same bearings for support as the forward and reverse gears
Propeller shaft
Has a set of splines machined into its surface at a point between the forward and reverse gears. Has a clutch shifter located on these splines
Propeller shaft
Long enough to allow the clutch shifter to slide forward and aft
Propeller shaft splines
Has castellations, or raised lobes, machined into both its front and backside. These are also known as drive lugs
Clutch shifter
Sets on the propeller shaft between the forward and reverse gears
Clutch shifter
Have castellated surfaces that match the drive lugs of the clutch shifter
Forward and reverse gears
_____ is transmitted to the propeller shaft as the clutch shifter is slid forward or aft into the forward or reverse gear
Torque
The pinion gear is constantly turning the forward and reverse gears in _____
Opposite directions
Splined to the propeller shaft, so when the forward or reverse gears turn it, the propeller shaft turns
Clutch shifter
The direction of propeller shaft rotation depends upon ____
Which direction the clutch shifter is moved
If the clutch shifter is slid forward
The propeller shaft will cause it to come in contact with the forward gear, and the propeller will spin in the forward direction
If the clutch shifter is slid aft
The propeller shaft will cause it to come in contact with the reverse gear, and the propeller will spin in the reverse direction
If the clutch shifter is held in the center position and not in contact with either gear
The propeller shaft will not move. This is the neutral position and the forward and reverse gears are still spinning
Used to slide the clutch shifter forward and aft on the propeller shaft splines
Shift rod and shift mechanism
Extends vertically from the shift mechanism in the gearcase up to the powerhead, where it links with the gearshift lever to allow the operator to shift gears
Shift rod
Has a pivoting lever that connects the shift rod to the clutch shifter
Shift mechanism assembly
Slides the clutch shifter through its range of travel on the propeller shaft splines
Pivoting lever or shift plate
Used to transmit the engines rotary motion into horizontal motion by rotating in and moving the surrounding water with blades set at a pitch
Propeller
Propellers are identified by two numbers
Diameter and pitch
Distance from blade tip to blade tip
Diameter
The amount of twist the blades have
Pitch
Theoretically this figured is the distance in inches the propeller would travel in one rotation through a solid
Pitch
Will determine which propeller provides the optimum speed while maintaining the proper engine RPMs
Water test
The proper RPMs for an engine will be found
In a table located in the service manual for that engine
RPMs will be stated as ____
A range
The proper propeller will cause the engine to
Run at the midpoint of the operating range (RPM), while allowing the boat to achieve best speed
Running an outboard above the operating range will
Cause certain damage to the powerhead
Running an outboard below the operating range will
Cause build up of carbon deposits in the powerhead, and may shorten its life
A propeller will generate _____ when the propeller shaft is not running parallel to the water’s surface
Steering torque
Adjustable to compensate for steering torque, allowing the propeller shaft to run parallel to the water surface
Trim tab
If the boat pulls to the left, move the trim tab to the
Right
If the boat pulls to the right, move the trim tab to the
Left
Tighten the trim tab screw to a torque of
35 - 40 inch pounds
Installed on the gearcase to prevent corrosion
Zinc anodes
Additional anodes may be bolted to the lower portion of
The transom-mounting bracket
____ engine installations don’t have trim tabs
Dual
Why don’t dual engine installations have trim tabs
The torque generated by each engine cancels the other out
Do not do what to zinc anodes or their mounting surface
Paint or coat
This anode should be renewed anytime the gearcase is disassembled
Bolted to the driveshaft bearing housing on the cooling water side
Four advantages of water jets or jet drives
Higher overall efficiency at speeds over 25 kts, superior maneuverability, no underwater appendages, high thrust at low speeds
Intake water from beneath the vessel, then push that water out the nozzle for the purpose of forward movement
Function of jet drive propulsion
Positioned flat against the hull of the boat
Base plate of the inlet grate
Ahead/astern movement of boat is controlled with this, infinitely variable between three positions to obtain speed and control needed
Reversing bucket
Sideways movement of the boat controlled, three main positions with infinitely variable positions inbetween
Steering nozzle
Contains a section of vanes that reduce the torque that is created from the impeller
Guide vane chamber
Highly refined mixed flow type capable of pumping large volumes of water at relatively low pressures
Impeller
Coupling is mounted on the main shaft forward of the bearing housing
Impeller housing
Used to connect the drive shaft to the engine and marine gear/reduction gear which in turn drives the impeller
Shaft flange
Zero thrust is obtained when the bucket is lowered about
70%
Common steering system found on vessels with jet drives
Electro-hydraulic steering system
Full steering lock starboard means
the steering nozzle is turned 30 degrees to starboard side
Keeps the hydraulic temperatures within parameters
Oil cooler
HPU
Hydraulic power unit
Oil cooler is mounted _____ and is connected to _____
On the side of the engine, HPU
Mounted on the main driveshaft forward of the bearing housing, where the engine connects to the jet drive shaft
Shaft flange
The driveshaft to the water jet must have
Axial and radial flexibility
Also called cardan shafts
Double universal slip-jointed driveshafts
Bolted directly to the engine reduction gear and shaft flange
Universal joints
Aid in the alignment of engine/reduction gear and the jet drive
Universal joints
The flange end of the shaft is held in the bearing housing by
An oil lubricated axial bearing
Keeps water from entering the bearing housing
Mechanical seal
On the underside of the bearing housing, there is an inspection hole which is checked ____
Monthly to ensure the seals are working propely
Before the engine is stopped, set the reversing bucket ______
Full ahead position so that the piston rod is inside the cylinder to prevent fouling and corrosion
Water jet unit must not be operated dry because
Rubber bearing and mechanical sealing require water lubrication
Engine starting systems consist of
Battery, key switch, starter solenoid, and starter motor
Basic theory of the starter systems operation and testing procedures for its basic components are found in
Manufacturer’s service manual
Supplies the needed voltage to turn the starter motor
Battery
Dictates the batteries type and rating
The size of the outboard engine
See this for the correct selection of replacement batteries
Manufacturer’s service manual
Never use ____ to fasten cables, always use ____
Wing nuts, lock washers and hex nuts
The positive terminal of the battery is connected to
One of the solenoid contacts
The negative terminal of the battery connects to
A common ground on the powerhead or engine section on the outboard engine
Operated by the boat driver, uses 12 volts from the battery to energize the coil inside of the starter solenoid
Key switch
Used only to energize the coil inside of the starter motor
Key switch
Key switch uses what gauge of wire
12 - 14 gauge
Opens the circuit to the starter solenoid and closes the stop circuit
Off position
Opens the circuit to the starter solenoid and keeps the stop circuit open
Run position
Closes the circuit to the starter solenoid and opens the stop circuit
Start positon
Protects the low amperage part of the starting system from damage due to faulty wiring or operator error
In-line fuse
Located in the wire supplying the voltage to the key switch, runs from the battery side of the solenoid contacts to the input side of the key switch
In-line fuse
Remotely operated, semiautomatic switch used to relay power from the battery to the starter motor
Starter solenoid
Has two separate circuits, both are 12 volts, but each requires a different amperage draw
Starter solenoid
This circuit uses two small terminals, which receive voltage from the key switch, and energizes the solenoids internal coil
Low amperage circuit
This circuit uses the two large terminals on the solenoid, and carries battery power from the positive terminal of the battery to the input of the solenoid
High amperage circuit
The output of the starter solenoid is connected to
The starter motor terminal
When the key is released from the start position, ____ pushes the copper washer away from the contacts, de-energizing the starter motor
A spring
Has an engine engagement gear mounted to the upper portion of its shaft
Starter motor
Cause the engine engagement gear to move upward along the starter shaft until it engages the engine
Spiral grooves along with centrifugal force
The engine engagement gear engages with
Ring gear that is cast into outer portion of the flywheel
Metal frame wound with wire, bolted to the top of the powerhead, directly under the rotating flywheel
Charge coil
On smaller HP outboards, the charging system use
Magneto
Charging system uses magnets bonded to the flywheel rotating around stationary coils to produce electricity
Magneto
When the magnetic poles and bosses on the coils align in the magneto
The magnetic field flows through the metal core of the coil
As the flywheel magnets rotate past the coil, they continually change the
Magnetic polarity of the coil bosses
The constantly changing magnetic field produces
AC electricity
The battery and accessories require electricity that is flowing
In only one direction
On larger HP applications, ____ is used to generate electricity by the same principle as
An alternator, DC generators
Uses a series of diodes to change AC electricity into DC electricity
Rectifier
Can be thought of as a one way check valve for electron flow
Diode
Current can only flow through a diode when the arrow side is more ____ than the vertical line side
Positive
Arrow side of a diode
Anode
Vertical line side of a diode
Cathode
Configuration of diodes that allow current flow if either input wire is positive
Full wave rectifier
Located within the voltage regulator/rectifier and changes AC electricity to DC electricity for the purpose of charging the battery
Full wave rectifier
All electric start outboards produced after ____ are equipped with a regulated charging system
1990
This system has all the components of a non-regulated charging system and performs the same function, except that it has the ability to turn on and off as needed, depending upon battery voltage
Regulated charging system
Key to a regulated charging system
Voltage regulator/rectifier
Voltage regulator/rectifier contains
Full wave rectifier, switchgear, wires for other accessories
Turns the charging system on when the battery reaches a low set point, and off when the battery voltage reaches a high set point
Switchgear
When in the off position the regulator/rectifier diverts the charging current
Safely to ground
For ease of component replacement, this is attached to the side of the powerhead. The alternator, regulator/rectifier, tachometer, and various other components are wired together using this
Terminal block
Most coast guard installed outboards use an ignition system known as
Capacitor discharge ignition
Stores the systems electricity in a capacitor until it is discharged to the ignition coil
Capacitor discharge ignition
Four advantages to capacitor discharge ignition systems
Less maintenance, more voltage, quicker spark, each cylinder has its own ignition coil
How much voltage created in a capacitor discharge ignition system
Up to 40000 volts
How quickly is the spark forced across the gap in a CD ignition system
Six microseconds
CD ignition system consists of five major components
Magneto or alternator, sensor/pulser coils, ignition control module or engine control module, ignition coils, spark plugs
Firing signal produced when
A magnet passes the sensor/pulser coil producing a small amount of voltage
The firing signal is processed by ___ then energizes the ____ to complete the circuit through the capacitor and primary winding of the ignition coil
Gate circuit, silicon-controlled rectifier
In the ignition coil the large, rapid current flow through the primary winding induces
Much higher voltage in the secondary windings, approximately 100 times more
The flywheel has ____ attached to its underside
Magnets
Coil of wire wrapped around a metal core. Mounted under the flywheel
Charge/exciter coil
As the flywheel magnets pass by the coil, they continually change the ____ of the metal core
Magnetic polarity
Magnet in the center of the flywheel, or under the cam pulley
Hub/cam magnet
Metal sleeves around the hug/cam magnet
Pole shoes
Wrap around the hub magnet and concentrate the magnetic flux at their ends
Pole shoes
The brain of the CD system
Ignition/engine control module (ICM/ECM)
Works in conjunction with the other components to produce an extremely fast, hot spark, sending it to the spark plug at the correct time
ICM/ECM
The diodes, full wave rectifier, capacitor, silicon controlled rectifier, and gate circuit are integrally cast into the body of ______
ICM/ECM
Capacitors cannot store
AC electricity
Used to rectify the current
Diodes
Direct electricity so when a charge coil wire is positive, that wire is connected to the positive side of the capacitor
Diodes
Configuration of diodes that allow current flow if either wire is positive
Full wave rectifier
The conversion of AC to DC current in the ignition system is used to
Charge and store current in the capacitor
In order to harness enough electricity that will provide a good spark, the electricity must be stored or collected in a device called
Capacitor
Can provide short powerful bursts of electrical energy
Capacitor
Sometimes called a thyristor
Silicon controlled rectifier
SCR
Silicon controlled rectifier
Very similar to a diode, but it has an additional lead called a gate
SCR
Will not pass current until the lead gate is energized
SCR
The gate lead is energized by
Pulser/sensor coil
Once the gate lead is energized, the SCR allows the capacitor to
Discharge or dump its charge to the ignition coil
Low voltage side of the ignition system
Primary circuit
Parts of the primary circuit
Charge/exciter coil, ICM/ECM, sensor/pulser coil
Does not create enough voltage to jump the spark plug gap
Primary circuit
Converts electricity from low voltage to very high voltage at the expense of amperage
Ignition coil
The ignition coil uses _____ to raise voltage
Electromagnetic induction
From the coil the electricity travels through what to the spark plug
High tension lead
Constructed of two coils of wire placed next to each other
Ignition coil
_____ winding has more windings than the ____. In the ignition coil
Secondary, primary
This winding produces higher voltage
Secondary
Typical ignition coil on an outboard has ____ turns of wire in the secondary and _____ turns of wire in the primary
2500, 25
Ignition coil winding ratio
100:1
To stop ignition
Alternate path for electricity stopped in the capacitor to discharge harmlessly into ground
Identifies the piston location in the cylinder while setting the timer pointer
Piston stop tool
First piston to receive spark in the ignition firing sequence
1
Components of the piston stop tool
Adapter, stop rod, lock wheel
Used to check idle timing and maximum spark advance
Strobe timing light
Attaches to and flashes a light in synchronization with the spark plug wire
Strobe timing light
The strobe timing light will flash up to ____ per minute
5500
Aim the strobe light at
The timer pointer
Used to determine the RPMs of the flywheel
Handheld electronic tachometer
Use ____ with the handheld electronic tachometer
Retro reflective tape
Mounted on the prop shaft in place of the standard propeller
Test wheel (test propeller)
Designed to put a load on the engine while creating only minimal water movement, allowing technicians to run the engine at maximum speed in a test tank
Test wheel
Two procedures that require a test wheel
Check engine operation by verifying minimum test propeller RPM rate, check maximum spark advance
Maximum test RPM rate can be found in
Engine specifications
Hand tool used to remove the fuel jets or orifices from carburator
Orifice driver
Measures the discharge pressure of high pressure fuel pump within the fuel rail
Pressure gauge
Measures the suction sides of the fuel system
Vacuum gauge
Tool indicates an excessive restriction in the fuel supply
Vacuum gauge
Contains a set of tools that bolt onto the flywheel and push on the crankshaft, pulling the flywheel from the powerhead
Universal puller kit
Doubles as a powerhead lifting device
Universal puller kit
Used to check total voltage output during ignition system checks
Spark tester
Hook the ____ to the spark tester
Spark plug wires
Meter that stabilizes and reads the uneven and spiked voltages from the flywheel magnets and associated coils during ignition system testing
Peak-reading voltmeter
Performs some of the same functions as the ohmmeter
Test light (continuity tester)
Comprised of a tiny light bulb with a small battery and two leads
Test light
The test light creates a _____ circuit
Series
Handheld instrument that performs some of the same functions as a heat sensitive marker, but measures heat electronically using infrared technology
Infrared temperature gun
Some infrared temperature guns include a ____ to increase accuracy
Laser pointer
Used to check the integrity of the oil and water seals in the lower unit
Geargase pressure/vacuum tester
Comprised of a hand operated reciprocating pump, pressure gauge with a one way valve, and an attached hose with a threaded adapter for installation into gearcase oil drain plug bore
Gearcase vacuum/pressure tester
Used to check the gearcase seals ability to hold a vacuum
Vacuum tester
Tool that provides a convenient way to fill gearcases with oil, and consists of a three gallon tank, pump, and quick disconnect hose assembly
Gearcase filler
The gearcase filler plug valve must be turned how far to change supply from full flow to closed
Quarter turn
Gearcase oil check should be done every ____
50 operational hours
Gearcase oil replacement should be done every _____
100 operational hours
only tool needed to perform an oil change
Flat head screwdriver
Weights of oil used for gearcase
80 or 90 weight
Avoid accidental starting of engine while servicing by
Disconnecting the battery and tagging engine out
Ensure air supply does not exceed ____ when using shop air for cleaning or drying
25 psi
Wen performing a lower unit or gearcase oil change, ensure the outboard is in a _____ position
Vertical or upright
Oil drain plug has what build in to collect metal chips
Magnet
Why does the oil drain plug have a magnet to collect metal chips
To alert technicians of possible internal gear problems
What happens when the top oil level plug is removed
Releases the vacuum that exists and allows the oil to drain freely from the lower unit
How long to drain all oil completely from lower unit
Five to ten minutes
While oil is draining, inspect ____
The seals (usually o-ring type) on both drain plugs for dry rot, cracks or tears. And inspect used oil
If drain plug o-ring/seal has dry rot, cracks, or tears
Replace with a new seal
If drain plug o-ring/seal does not have dry rot, cracks, or tears
Lubricate and reuse
If used gearcase oil appears milky indicating the presence of moisture
Consult with your supervisor, as internal problems may exist
If used gearcase oil is gray or smells burnt
Consult with your supervisor, as internal problems may exist
Milky oil indicates
The presence of moisture
If oil drain plug has large metal chips
Consult with your supervisor, as internal problems may exist
If the oil drain plug has fine metal filings
This indicates normal gear wear
One of the more popular oil filling methods
Squeeze bottle
Insert the gearcase filler into
The bottom drain hole
Tighten the oil drain plugs how tight
Hand tight
Maximum allowable variation between compression of different cylinders
15 psi
Possible causes of uneven cylinder compression
Damaged head gasket, damaged pistons, broken or stuck piston rings, scored cylinder walls, stuck valves, incorrectly adjusted valves
Tool used to measure proper compression pressures within the engine’s cylinders
Compression tester
Comprised of a pressure gauge with an attached hose. The end of the hose has an adapter for threading into spark plug holes. The gauge has a built in check valve
Compression tester
Two types of common compression testers
Threaded and hand held
First step to obtain compression reading
Run the engine until it reaches normal operating temperature
When checking compression crank engine at least this many times through the compression stroke
Four
Spark plugs should be replaced when the engine reaches its first _____ hours
100
Most spark plug insulators are made of
Porcelain or ceramic
When replacing spark plugs, set the gap toward
The tight end of the spectrum
The center electrode of a spark plug is made of
A nickel-iron alloy
The basic types of spark plug fouling
Carbon fouling, lead fouling, oil/carbon fouling
Caused from low speed operation or a fuel mixture that is too rich. Causes missing or roughness and creates soft black soot that is easily removed (spark plug)
Carbon fouling
Caused by tetraethyl lead used in some fuels and by high speed operation (spark plug)
Lead fouling
Appears as a heavy, crusty formation, or as tiny globules (spark plug)
Lead fouling
Found on four stroke engines that are so badly worn that excess oil reaches the combustion chamber past the piston ring or the valve guides (spark plug)
Oil/carbon fouling
Set the gap clearance of a spark plug with
Wire-type feeler gauge
When reinstalling used spark plugs, tighten them ___ after the spark plug seats
1/8 - 1/4 turn
When installing new spark plugs, tighten them ____ after the spark plugs seat
1/2 turn
Apply a thin coat of ___ to the ribbed portion of the spark plug insulator and the opening of the spark plug wiring boot
Waterproof grease
Size of socket bolt securing the ignition coil
6 x 25 mm
Adjust the air gap between the points on the spark tester to
1/2 inch
To prevent possible arcing, route the leads ___ from any metal surface for the spark tester
Two inches
Most common type of fuel filter in the coast guard
Spin on type
Fuel filters are rated by
Micron size or gallons per hour
Clean the fuel strainer with
Low pressure air
Install the fuel suspension to the strainer; align the “I” mark on the tube with
The direction of exit side of the fuel tube joint
Test the water level sensor in the water separator by
Connecting a fluke meter on the two leads to the 2P connector and setting the meter to read continuity
If the sensor is level (the float is down) on the water separator
There should be no continuity
If the sensor is turned upside down (the float is up) on the water separator
There should be continuity
To measure belt tension using a belt tension gauge, pull at
The center between the pulleys
Size of flange bolt located behind the alternator
10 x 90 mm
Size of flange nut located behind the alternator
8 mm
Use this bolt to adjust alternator belt tension
Special adjuster bolt
Controls the valve timing in four stroke engines
Timing belt
The crankshaft drives the camshaft via
The timing belt
After aligning the timing belt driven pulleys no. 1 TDC marks with the marks of the timing belt back cover, slowly turn the crankshaft pulley counter clockwise further by _____ teeth of the timing belt driven pulley gear
5
Apply a force of _____ at the midpoint between the left side timing belt driven pulley and the idler pulley B
19.6 N (4.4 foot pounds)
To adjust the timing belt loosen the timing belt tensioner bolt _____
Approximately one and one half turns
If the ignition pops or backfires during starting
The ignition may be out of time
Assures timing pointer is aligned with the correct spot on the flywheel grid during ignition checks
Set timing pointer
Sets carburetor’s linkage so the throttle plates in the throats of the carburetors begin to open at the same time and travel the same distance
Synchronize throttle plate
Sets the throttle linkage so the carburetor’s throttle plates begin to move at the correct moment in relationship to the advancement of the ignition timing
Cam follower pickup
Sets the throttle linkage so the carburetor’s throttle plates begin to move at the correct moment in relationship to the movement of the throttle cable
Throttle cam
Sets a limit on throttle movement
Wide open throttle stop
Requires a strobe type timing light and allows the technician to set the timer base so the spark plugs fire at the optimum moment during idling
Idle timing
For most four stroke engines, the only synchronization needed is
A simple adjustment of the throttle control cable and shift control cable
Occurs when at least two different metals are brought into electrical contact underwater and form a galvanic couple
Galvanic corrosion
Once the galvanic couple forms, the weaker metal in the couple becomes the ____ and corrodes faster, while the other becomes the ____ and corrodes slower
Anode, cathode
Act as a sacrificial metal to prevent galvanic corrosion
Anodes
Test anodes for proper installation with
An ohmmeter
Replace water pump at least _____
Annually
Lock the new impeller liner in the new impeller housing for the water pump with ___
The square index tab
Install the new impeller for the water pump with what motion
Counterclockwise rotation
Verify the impeller for the water pump engages the
Impeller cam
Install the water tube grommet with ____ facing up
the inside chamfered edge
Apply ____ to the groove of the impeller housing grommet for the water pump
Thin bead of adhesive sealant
The _____ edge of the cam is the leading edge during driveshaft rotation for the water pump
Sharp edge
