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127 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Name The 3 Engine Types |
1. Inboard engine with shaft-drive system 2. Inboard engine with out-drive system 3. Outboard engine |
which one has a shaft-drive, which one has an out-drive? |
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What are the suitable vessel sizes for each of the 3 engine types? |
1. Inboard engines with shaft drive system: 38 feet or above 2. Inboard engine with out drive system: 38 feet or below 3. Outboard engines: below 30 feet (can be lifted completely out of the water) |
between 30 and 40 feet? |
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What is the purpose of a swan neck? Where is it located? |
A "swan neck" appears in the exhaust and stops water from going inside the engine. |
you only see it in an inboard engine with shaft drive system! |
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Can an inboard engine with out-drive system be lifted out of water? |
only partially - it will have limitations in shallow water. |
there are limitations in shallow water... |
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What are the 3 main sections of an engine? |
1. Cylinder Head (inlet and exhaust valves are here) 2. Engine Block (cylinders are located here) 3. Crankcase (the crankshaft rotates here) |
top section is the "head" middle section is the "block" bottom section is the "case" |
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Where does air come in to an engine? What is it connected to? |
Air inlet is connected to the air filter. |
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What is the importance of the air filter? (3 things) |
1) clean air intake 2) silencer 3) flame trap |
for safety and anti-noise? |
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What is the appropriate tightness of a V-belt? |
1/2" - 1" when pressed down with a thumb. |
its in inches |
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What is an alternator? |
Generator/battery. |
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What is the water pump used for? Where is it located? |
For cooling the engine, and can be found by the V-belt. |
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What are the 2 jobs of the flywheel and what is it made of? |
The flywheel helps stabilise the boat and stores energy during expansion, releasing it during the other strokes to smooth the rotation of the engine. It is made of heavy cast iron or stainless steel. |
What does it store? |
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What is special about the oil drain plug? |
It has a magnet to collect metallic fillings |
It is used to collect something... |
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What is the component that stores the oil? |
Oil sump |
Starts with an "s"... |
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What happens when the V-belt is broken? |
There will be no stream by the side of the boat and the temperatures will be high. |
The water pump wont work... and you can't see something by the side of the boat...? |
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What is a dipstick? |
It is a rod used to check oil amount |
It is used to check something? |
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What is important when checking the oil? |
Check the oil only when its COLD! |
you don't want to burn yourself... |
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What does the oil sump store? |
Stores lubrication/engine oil (please top up with the SAME oil!) |
two "types" of oil! |
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What is the name of the component used to seal the cylinder head with engine block? What is it made of? |
It is called a gasket, which is made of synthetic material |
starts with a "g"... |
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How can a gasket be damaged and what can happen? |
It can be damaged by an overheated engine. 1) cooling water and engine oil may mix together 2) compressed air in the cylinder may escape to the cooling circuit or vice versa The engine will eventually stop due to mechanical failure. |
What happens to fluids and gases? |
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What happens when water enters a cylinder? |
The connecting rods on the piston will break, and then engine will get stuck. |
the pressure will be damn high! |
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What are the symptoms of water entering the cylinder/ broken piston? |
Engine will be hard to start, or it cannot hold an idle speed |
remember there are two things! the engine is basically dying... |
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What are the two ways to check if water has entered the cylinder and broke the engine? |
1. Look at the fresh water tank for bubbles or oil (usually its just distilled water but you may put some anti-rust solution in it) 2. Water may also leak into the oil sump for smaller boats, so you can check with a dipstick to see if there is an emulsion (milky) |
It can leak into two tanks... |
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If an engine has 2 cranks, how many cylinders does it have? |
2 cylinders |
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What are the 4 main steps of a 4-stroke engine? |
1. Induction (draws air) 2. Compression 3. Expansion 4. Exhaustion (expels air) |
air in... push/pull.. air out |
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Explain the anatomical structure of how the crankshaft rotates |
When air expands, the piston gets pushed down. The connecting rod which is connected to the crankshaft via cranks, essentially transfers up/down movement to rotary movement. |
mention at least 4 main components! (starting from the piston) |
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How many rings does a piston have? |
There are total of 3 Piston Rings. 2 rings for air and 1 for oil. The air ring ensures a gas-tight fit in cylinders. The oil ring is honeycomb like and effectively pushes oil back into the sump |
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What are the symptoms of water burning? |
White smoke |
what color smoke? |
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What are the symptoms of oil burning? |
Blue smoke |
what color smoke? |
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Explain the anatomical structure of how valves open/close |
While camshaft rotates, the egg-shaped cam pushes the tappet/cam follower which is connected to the push rod up. the rocker arm then pushes the valve spring down, opening the inlet/exhaust valves. |
mention 6 main component (starting from the camshaft!) |
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Where is the rotation from crankshaft transferred to eventually? |
Gearbox and propeller shaft |
the boat needs to move... but how? |
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What is the component used to transfer rotation of crankshaft to cam shaft? |
Timing gear |
One is faster than the other! |
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What is the timing gear used for? |
To transfer rotation of crankshaft to camshaft |
Which shafts move at different speeds? |
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On 4-stroke engines, how many times does a crankshaft rotate vs a camshaft during each complete cycle? |
A crankshaft rotates two revolutions (aka two full circles, 720 degrees), while a camshaft rotates one revolution (360) |
A camshaft opens/closes once per cycle! |
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On a 4-stroke engine, how much does a crankshaft rotate per stroke? What about a camshaft? |
Crankshaft - 180 degrees Camshaft - 90 degrees |
A camshaft opens/closes once per cycle! |
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What is the purpose of a gasket? |
It is placed between the cylinder head and engine block to keep gas and fluid tight. |
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What are the holes in a gasket? |
They are the water/lubrication circuits. |
what two things run between the engine parts? |
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What is the physical difference between a water circuit and a lubrication circuit? |
Water circuit: has metal ring Lubrication circuit: no metal ring |
one ring looks different... |
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What is the cylinder to crank ratio? |
1:1 |
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How and where is a piston connected to the connecting rod? |
It is connected at the small-end bearing with a gudgeon pin |
starts with a "g"... |
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Where is a connecting rod connected to the crankshaft? |
It is connected at the big-end bearing of the connecting rod |
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What is the crank to cam ratio? |
1 crank: 2 cams |
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What are the two symptoms of worn-out bearings? |
1. knocking 2. low oil pressure |
sounds and oil |
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What is the max engine speed of these engine types? 1) engine with a normal push rod 2) side cam engines with a shorter push rod 3) overhead cam engines with no push rod |
1) 2000rpm 2) 4000rpm 3) 6000rpm |
the longer it takes, the slower it is... |
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How much teeth do the crankshaft gear have vs the camshaft gear? |
crankshaft - 10 teeth camshaft - 20 teeth (moves at half the speed) |
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What does the push rod do? |
It causes the rocker arms to pivot, opening/closing the valves |
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What is the appropriate clearance distance between rocker arms and valve stem? How do you measure this? |
0.025" is normal clearance (or refer to manual). You measure this by placing a feeler gauge (thin metal piece) between rocker arm & spring gap |
its in inches and starts with an "f"... |
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What happens when the clearance is too small? |
Valves don't close properly - compression may not be achieved |
Which step (out of the 4) wont work properly? |
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What happens when the clearance is too big? |
Valves don't open fully and causes noisy valves (as the rocker arm is "hitting" against it) |
the rocker arm is hitting against the spring! |
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Is there a difference between the clearance of exhaust valve and inlet valve? |
Clearance of the exhaust valve is larger due to higher heat expansion ratio |
yes, one is larger... |
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What does BDC stand for? |
Bottom Dead Centre - position of the piston in the cylinder closest to crankshaft |
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What does TDC stand for? |
Top Dead Centre - position of the piston in the cylinder farthest from crankshaft |
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Explain what happens in Induction (3 steps in terms of piston, valves and air) |
1. Piston goes down from TDC to BDC 2. Inlet valve is open 3. Cold air-fuel mixture is drawn into the cylinder |
something comes in |
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Explain what happens in Compression (3 steps in terms of piston, valves and air) |
1. Piston goes up towards TDC (crankshaft rotates 180) 2. Both valves are closed 3. Air-fuel mixture is compressed |
something is squashed |
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Explain what happens in Expansion (3 steps in terms of piston, valves and air) |
1. As piston gets closer to TDC, spark from spark plug ignites the air-fuel mixture (crankshaft rotates 180) 2. Piston is forced downwards to BDC 3. Both valves are closed |
something gets really hot |
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Explain what happens in Exhaustion (3 steps in terms of piston, valves and air) |
1. Piston goes up towards TDC (crankshaft rotates 180) 2. exhaust valve is open 3. Exhaust gases are forced out |
something leaves |
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what does rpm stand for? |
revolutions per minute |
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If a 4 stroke engine has a speed of 1000rpm, what is the ps/min for a single cylinder engine? |
500 ps/min |
1) 1000 revolutions = 1000 circles 2) a power stroke occurs once every 2 cycles (the expansion) |
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If a 4 stroke engine has a speed of 1000rpm, what is the ps/min for a 4-cylinder engine? |
500 ps/min x 4 cylinders = 2000 ps/min |
single cylinder = 500 ps/min |
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What is a valve lead? (2 instances) |
1) When the inlet valve opens before TDC 2) when the exhaust valve opens before BDC |
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What is a valve lag? (2 instances) |
1) When the inlet valve closes after BDC 2) when the exhaust valve closes after TDC |
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what is valve overlap? |
During the TDC period, the inlet valve opens a bit before TDC and exhaust valve closes a bit after TDC, so both valves are open at the same time to clear exhaust gases completely. |
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How many power strokes are there in one complete cycle on a 4-cylinder 4 stroke engine? |
4 power strokes (one from each cylinder) |
1 cycle = 1 power stroke for one cylinder |
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What is the firing order of a 4-cylinder 4 stroke engine? |
1,3,4,2 (to get a balanced operation on the engine) |
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What is used to check ignition timing? |
A timing gun |
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What is the compression ratio? |
X - piston working volume Y - clearance volume
Compression ratio = X + Y : Y |
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what is clearance volume? |
volume left in the cylinder when piston is at TDC |
has to do with the cylinder |
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what is the piston working volume? |
volume in the cylinder between TDC and BDC |
has to do with the cylinder |
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What is the general compression ratio of a petrol engine vs. diesel engine? |
petrol: 10:1 diesel: 20:1 (longer, higher torque) |
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What is the importance of a vent pipe? |
Maintain atmospheric pressure inside the tank |
its a "breathing" hole... |
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What is at the opening of the vent? Why? What is it made of? |
Flame trap (aka copper gauze) is installed to remove heat from a flame and stop it from entering the tank. |
some kind of gauze |
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What should be done to maintain a fuel tank? |
Regularly drain the fuel tank of water or always fill it up after use to avoid condensed water (from air moisture) inside the tank and prevent tank corrosion or engine stopping (fuel mixed with water is bad for it) |
it gets pretty humid... |
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What is the name of the component to drain water from a fuel tank? |
Water release valve |
its a valve |
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Where is the water release valve located? How do you drain water? |
At the bottom of the fuel tank. As water is heavier than fuel, drain until you see fuel. |
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What is the flash point of petrol vs diesel? |
Petrol: -44 degrees Diesel: +65 degrees so petrol is much more flammable and dangerous! |
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Name the 5 important steps during refueling |
1. tie boat properly to fuel dock 2. close all windows and hatches 3. passengers stay ashore 4. ground fuel nozzle to fuel filling point 5. ready the foam type fire extinguisher |
the boat, the people, the nozzle... and something else just in case. |
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What happens when you mix diesel oil with petrol oil? |
The engine would stop running |
nothing serious (i think) |
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Why is it important to ground fuel nozzle to fuel filling point? |
If nozzle hits against the filling point, there will be a spark |
its a fire hazard! |
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What is another name for the fuel pump? What is special about its valves and how is it operated? |
The diaphragm pump transfers fuel from the tank to the engine by the camshaft. The valves are non-return. |
which shaft moves it? |
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What does a carburettor do? Which engine type has one? |
Petrol engines only - it mixes the air with fuel before entering the cylinder |
mixes something! |
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Name all the components of the carburretor |
1. choke 2. main jet 3. butterfly/throttle valve 4. idle jet (slow speed pipe) 5. float 6. needle valve 7. venturi |
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What is the purpose of a choke? When can we release it? |
For cold starts - controls air to fuel ratio Closing it will cause a vacuum when air is drawn into the intake manifold, causing the pressure difference to be greater, and a larger amount of fuel to mix with the air to enrich it. Release it once the engine is warmed up. |
what happens to the air when the choke closes? |
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What is the purpose of the throttle valve? |
Does NOT control air to fuel ratio! It simply adjusts the amount of air-fuel mixture passing into the intake-manifold. Closed = very little mixture is let through (decelerating) and vice versa. |
what does it stop from entering the cylinder? |
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What is the purpose of the Venturi? |
When air passes, the air speed increases, causing pressure to decrease. the difference in pressure between here and the float chamber forces fuel to be let in through the main jet (from high to low) and mixed with the air. |
the area is smaller so... |
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What does the needle valve do? |
It shuts off the fuel supply into the float chamber when it reaches maximum level |
its connected to the float |
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What is the difference between the main jet and the idle jet? |
The idle jet is for supplying fuel when the boat is at slow speed/idling (around 800 rpm), while the main jet is for 800 - 6000rpm. |
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where are the 3 places you will find a flame trap? |
1) vent pipe 2) air filter 3) drip tray at the bottom of the engine |
engine top, engine bottom and fuel tank |
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What is the purpose of an intake manifold gasket? |
Prevents air outside (higher pressure) from leaking in. If it is leaking, mixture will be leaner. |
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What controls the air-fuel mixture ratio when idle and where is it located? |
Mixture control screw and it is located in the idle jet |
its a screw |
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What is the advised throttle setting when warming up the engine? What is a good way to check this? |
Operate 1/4 of the throttle for 10 minutes to warm it up - check by spark plug color. |
position and timing. |
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What are the symptoms of a lean air-fuel mixture? (4 total) |
1. white spark plug deposit
2. pre-ignition (early ignition) 3. cylinder knocking 4. engine vibrations and lack of power |
spark plug, timing, noise and weird engine movement |
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What are the symptoms of a rich air-fuel mixture? (5 total) |
1. black emission 2. black spark plug deposit 3. spark plug will be too wet to start 4. engine stops after warm up 5. carbon build up in exhaust manifold |
smoke, spark plug, engine x2, exhaust manifold |
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What is a fix for an overly rich air-fuel mixture? |
Cut fuel from the tank, and crank until the cylinders are dry. Release fuel back into the tank afterwards. |
repetition until spark plug is dry |
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What are two causes of a rich mixture, besides wrong adjustments |
1. dirty air filter - too little oxygen 2. overloading the engine (e.g. if the boat bottom is too dirty, causing drag) |
quality of air, and quality of the boat |
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What is a cause of a lean air-fuel mixture, besides wrong adjustments? |
1. leaking gasket in the intake manifold |
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Name these ignition components |
A. battery B. switch C. primary winding D. induction coil E. secondary winding F. lobed cam G. contact breaker H. condenser I. rotor arm J. spark plug K. distributor cap L. ignition distributor |
K - is 3D l - is the whole thing |
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how many windings does the primary winding have? What is its main characteristic? |
6000 windings. It has a thicker wire. |
appearance wise, how is it different from the secondary winding? |
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how many windings does the secondary winding have? What is its purpose? |
20,000 windings. It converts low voltage (12V) to high voltage (over 20,000V) and creates a spark when the high voltage jumps across the gap on a spark plug, igniting the air-fuel mixture. |
it converts something? |
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What is the purpose of a contact breaker? |
It opens and closes at precise intervals, timing when the very high voltage is produced in the secondary winding. |
it times something important during ignitiong |
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What is the name of the component which controls when a high voltage is produced during ignition? |
Contact breaker. |
two words, starts with a "c" |
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How big is the clearance of a contact breaker? |
0.25 - 0.5mm (10 - 20/1000 inches) |
its in mm |
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What happens when the clearance of a contact breaker is too big? |
Advanced ignition timing |
the gap is created too early! |
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What happens when the clearance of a contact breaker is too small? |
Retarded ignition timing |
the gap is created too late! |
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What is the purpose of the condenser? |
I don't know. "prevent arcing across points of the contact breaker, protecting it from burning or pitting" |
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What is the ignition distributor driven by? What is the speed of it compared to the engine? |
The camshaft. It rotates at half the speed of the engine. |
which shaft makes the distributor move? |
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What is important about the condition of the distributor cap and high tension wires? |
It must always be kept dry. |
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What is the key disadvantages of a sea water (direct) cooling system compared to fresh water? |
1) Corrosion from salt water |
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What is the effective working temperature for engines? |
Between 80 - 90 degrees. |
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Thy is the temperature in a sea water cooling system compromised to around 60 degrees? What disadvantage does this have? |
To prevent sea water deposits (salt). It results in less efficiency. |
it prevent something. Plus the water is not so hot anymore... |
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What is the average temperature of a sea water cooling system? |
60 degrees |
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What is the purpose of a thermostat in the cooling system? |
It enables to engine to warm up quickly and prevents it from over heating (keeps the coolant at an optimal temperature) |
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If a thermostat is stuck open, what happens? |
The coolant will be too cool and the engine will take longer to warm-up |
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If a thermostat is stuck closed, what happens? |
The coolant will be too hot and the engine will over heat. |
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How and where is a fresh water cooling system cooled? |
As it circulates the engine, sea water pipes in the heat exchanger. |
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What component controls the inlet of a cooling system? Where is it located? When must it be on/off? |
Sea-cock (ball type cock), and it is located in the deepest part of the hull. It must be turned on before engine start and off when engine stops. |
its a ball... and very deep (in the water)..... |
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What is the purpose of an expansion tank? |
It gives an area for water to flow when it heats up and expands |
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What is the physical characteristic of the expansion tank cap? What is it used for? (4 advantages) |
It is loaded with springs and keeps the tank under optimal pressure. This is so: 1) the coolant can maintain a optimal high temperature (90 degrees) 2) maintain efficiency 3) less corrosion in engine 4) coolant is delivered more evenly throughout the engine |
temp, maintain something, engine, delivery |
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What is the fresh water pump driven by? |
V-Belt. |
what makes it move dude? |
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What are the two types of water pumps? (they each have two names) |
1. Fresh water pump (centrifugal pump) 2. Sea water pump (impeller pump) |
one is plastic |
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What is the main drawback of a fresh water (centrifugal) pump? |
It requires priming (using water to force air out from pump) before initial working. |
before initial working...? starts with "p" |
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What is the main drawback of a sea water (impeller) pump? What does it cause? |
Though it doesn't require priming, it needs regular replacement. Broken impeller pumps lead to insufficient cooling and an overheated engine. |
it doesn't need priming... |
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What are 5 common causes of a overheated engine from the cooling system? |
1. sea cock is blocked up 2. heat exchanger is dirty or cooling circuit is blocked 3. impeller is broken or v-belt is broken 4. thermostat is stuck closed 5. running a slow engine for too long |
a component, poor state of components, something is broken or stuck (2), engine |
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What is an air cooling system equipped is and what is its characteristic? |
Equipped with conductive fins, it is noisy and inefficient for vessels |
shhhh.. |
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Wet exhaust pipes are fitted with what and to where? |
They are fitted with rubber hoses to the transom of the vessel. |
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What are the advantages (3) and disadvantages (2) of a wet exhaust pipe system? |
Advantages: 1) Lower engine noises 2) lower the exhaust temperature 3) lower risk of fire Disadvantages: 1) Corrosion 2) Sea water may enter engine cylinders |
shh and cooler! broken and leakage! |
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What is the component that reduces gas flow rate and pressure? What does it do? |
Exhaust muffler, and it reduces exhaust noises. |
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How does an exhaust muffler reduce exhaust noise? |
It reduces gas flow rate and pressure |
it reduces 2 things... |
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Where is the exhaust muffler positioned? |
At the end of the exhaust pipe |
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