By: Zane Taylor Click the arrow to advance

 Click the Forward arrow to move to the next slide and the back arrow to go to the previous slide.  As you move through the assignment, you will learn the advantages and disadvantages of 2 and 4 stroke engines, then you will take a short quiz.

Hello, I run a lawn service company but my chainsaw and lawn mower have stopped working. Can you come and see what the problem is? You work at a small engine maintenance and repair shop. However, in the shop, you follow the instructions in the book and follow the advice of your boss. Today, you are the person who is making the field calls today and you’re not sure what to do in this situation. You need a quick course to learn how to tell the difference between 2 and 4 stroke engines.

2-Stroke4-Stroke QUIZ

 2 stroke engines do not have poppet valves. The sides of the piston work to cover the intake and exhaust ports.  Since there are only 2 strokes of the engine, the engine fires on every revolution which continually generates power.  These engines are also lighter and cheaper to make since these engines are made of Aluminum.  These engines, since they have a mixture that is ignited, can work in any orientation because of the way the engine is made..

 2 stroke engines require a special oil and a special ratio (4 oz. oil/ 1 gallon of fuel.)  These engines produce a lot of pollution since the design is not the most efficient and a very small amount of unburnt mixture escapes through the exhaust valve.

 These kinds of engines are used in chainsaws, leaf blowers, dirt bikes, mopeds, jet skis, small outboard motors, and RC planes.  The mixture ignited in the chamber is AIR/FUEL/OIL  The 2 strokes that are paired are INTAKE/COMPRESSION and COMBUSTION/EXHAUST.

1. What kind of mixture is sent to the combustion chamber? A. Air/Fuel Air/Fuel B. Air/Fuel/Oil Air/Fuel/Oil C. Fuel/Oil Fuel/Oil D. Air/Oil Air/Oil Click the correct answer to continue.

The mixture sent into the combustion chamber is Air/Fuel/Oil. Click the arrow to continue

Think back, there are 3 components of the mixture. Click the arrow to return to the question

 Which of these uses a 2- stroke engine? A. Chainsaw B. Car C. Dirt Bike D. A and C

 A car is too heavy to have a 2-stroke engine, however a chainsaw and a dirt bike are both light enough and maneuverable to merit the benefits of the 2-stroke. Click the arrow to advance

 If a chainsaw has a 2-stroke engine, think back and try to remember if there is another one that may have it. Click the arrow to return to the question

 A car isn’t light enough to have a 2-stroke engine, think about what the 2-stroke engines can handle. Click the arrow to return to the question

 If a Dirt Bike has a two-stroke engine, wouldn’t something smaller have one too? Click the arrow to return to the question

 What is the oil/fuel ratio in a 2-stroke engine? A. 4 oz./ 1 gal B. 4 oz./ 1 liter C. 6 oz./ 1 gal D. 6 oz./ 1 liter

 The correct ratio is 4 oz./ 1 gal Click the Home button to return to the Main Menu.

 Check back in the information to see what the ratio is. (Hint: Its oz/ gal)

 The 4-stroke engine does have better fuel economy than the 2 stroke engine.  The 4-stroke engine generates more torque than the 2-stroke.  Since the 4-stroke engine is heavier, it is more durable than its 2-stroke counterpart.  These engines do have cleaner emissions since they don’t mix the gasoline and oil when they are firing.

 These types of engines are more complicated since there is more timing required for these engines to work.  The 4-stroke is only half as powerful as its 2- stroke counterpart because the 4-stroke fires on every OTHER crankshaft rotation rather than every time.

 Only engines with a camshaft, valve train, and poppet valves.  Can run with gas, diesel, kerosene, whiskey, vegetable oil, rocket fuel, and gunpowder.  4-stroke engines are commonly found on Lawn Mowers and anything larger than that.

 What are 4-stroke engines commonly found on? A.Riding Lawn MowerRiding Lawn Mower B.ChainsawChainsaw C.Hedge TrimmerHedge Trimmer

 Correct, the riding lawn mower is too heavy to handle the 2 stroke engine but the 4 stroke is just right. Click the arrow to advance to the next question

 Think back, the 4 stroke is heavier than the 2 stroke and the 4 stroke is meant for bigger equipment. Click the arrow to return to the question

 What is one advantage of a 4 stroke engine over a 2 stroke engine? A. More DurableMore Durable B. LightweightLightweight C. Fires on every rotationFires on every rotation

 One advantage of the 4-stroke engine is that it is more durable than its 2-stroke counterpart Click the arrow to advance

 Think back about what the 2 and 4 stroke engines are made of and how they work.

 If you have not completed both reviews click on the Home button to go back to the Main Menu, otherwise click the arrow to advance to the next part of the lesson.

 One last thing before you go out to that job. You need to prove your knowledge with this short quiz.

 What is the mixture ignited in the chamber of a 2-stroke engine? A. Fuel/Oil Fuel/Oil B. Air/Fuel Air/Fuel C. Air/Fuel/Oil Air/Fuel/Oil D. Air/Oil Air/Oil

 That is incorrect. Go back to the question and remember, there are 3 components of the mixture.

 That is the correct answer. The mixture is Air/Fuel/Oil. Click the arrow below to go to the next question.

 What is one DISADVANTAGE of a 4-stroke engine? A. More Pollution More Pollution B. Requires Special Oil Requires Special Oil C. More Complicated More Complicated

 One disadvantage of the 4-stroke engine is that it is a little more complicated. Click the arrow to advance to the next question.

 Think about how the engine works and what it is made of.

 What is one ADVANTAGE of a 2-stroke engine? A. Lighter Lighter B. More Durable More Durable C. More Fuel Efficient More Fuel Efficient

 Think about the advantages of a two stroke engine. Specifically, the weight of it.

 The 2-stroke is lighter than the 4-stroke engine. Click the arrow to advance to the next question

 What are the 4 strokes of the engine, IN ORDER? A. Intake, Compression, Combustion, Exhaust Intake, Compression, Combustion, Exhaust B. Intake, Combustion, Exhaust, Compression Intake, Combustion, Exhaust, Compression C. Exhaust, Combustion, Intake, Compression Exhaust, Combustion, Intake, Compression D. Combustion, Intake, Compression, Exhaust Combustion, Intake, Compression, Exhaust

 Think about the order of the strokes. When you think about it, they will fall into order in your head.

 That is correct. You are now halfway done!  Click to Advance to the next question.

 What equipment is a 4-stroke engine commonly found upon? A. Chainsaw Chainsaw B. Hedge Trimmer Hedge Trimmer C. Riding Lawn Mower Riding Lawn Mower D. Leaf Blowers Leaf Blowers

 Think about the weights of the engines and how the pieces of equipment are used.  Click to return to the question

 The 4 stroke engine is commonly found on riding lawn mowers.  Click to Advance to the next question

 What are 2 stroke engines typically found on? A.ChainsawsChainsaws B.Hedge TrimmersHedge Trimmers C.Dirt BikesDirt Bikes D.All of the AboveAll of the Above

 Think about the way this is used, there may be more than one right answer.  Click the arrow to return to the question

 All of these options have 2 stroke engines on them.  Click the arrow to advance to the next question

 What is the fuel/oil ratio in a 2-stroke engine? A. 4 oz./ 1 gal B. 4 oz./ 1 literB. 4 oz./ 1 liter C. 6 oz./ 1 galC. 6 oz./ 1 gal D. 6 oz./ 1 literD. 6 oz./ 1 liter

 Think about what units we deal with. It is not too large of a ratio.  Click to return to the question

 That is the correct answer. You may remember that question from earlier.  Click to advance to the FINAL QUESTION

 What did the man at the beginning own that he needed your help with? A. Lawn Mower/Chainsaw Lawn Mower/Chainsaw B. Chainsaw/Hedge Trimmer Chainsaw/Hedge Trimmer C. Lawn Mower/Hedge Trimmer Lawn Mower/Hedge Trimmer

 What would be common in an agriculture community?  Click to return to the question

 CONGRATULATIONS, YOU HAVE COMPLETED THE QUIZ  Click to Advance

 You have completed your refresher course in just enough time to get to the job and do your job correctly!  Click anywhere to complete the lesson