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
