Small Engines Test
A. Short Answer Questions - Please answer the following questions in the space provided.
1. What are the 4 stages of a 4-cycle engine? Please use technical terms. (4 marks)
2. What is the primary function of the carburetor? (2 marks)
3. What is the function of a governor? (2 marks)
4. What is the function of a venturi? (1 mark)
5. In the ignition system of a small engine, what are the two main components that induce
current? (2 marks)
6. What is the function of the condenser? (2 marks)
7. The spark plug needs a high voltage so current can jump the plug gap. How is high
voltage induced in the ignition system? (3 marks)
8. What is the purpose of having a ceramic insulator around the spark plug electrode?
9. What is a black spark plug electrode indicative of? (1 mark)
10. What is a black and oily spark plug electrode indicative of? (1 mark)
11. What does a spark plug electrode look like when an engine is burning too hot? (1 mark)
12. What are 4 examples of functions that oil performs in any engine? (4 marks)
13. What are 2 functions that the flywheel performs in a small engine? (2 marks)
14. Define viscosity. (1 mark)
15. What is the main difference between single grade and multi grade oils? (2 marks)
B. Fill in the blank(s). (1 mark per blank)
1. During the intake stroke of a 4-cycle engine, the intake valve is ___________ and the
____________ pressure created by the downward stroke of the piston forces the air/fuel
mixture in the combustion chamber.
2. There are two plates or valves in the carburetor that air must pass through to get to the
combustion chamber. The first plate that air passes is the _____________ plate, and the
second is the _____________ plate.
3. The screw that adjusts the amount of fuel that leaves the fuel bowl is called the
___________________________. The screw that adjusts the fuel allowed in the air/fuel
passage way during engine idle is called the _________________________.
4. The __________________ pressure in the combustion chamber allows the air to enter the
engine due to the ______________________ pressure in the atmosphere.
5. The approximate ratio of air to fuel that is ideal for engine operation is ___________.
6. In the ignition system, the iron laminated core has primary and secondary windings. The
_____________ windings have thicker wire and less turns of wire, whereas the
_______________ windings have thinner wire and more turns of wire.
7. In an electrical circuit, a(n) ___________________ circuit has current flowing in it,
whereas a(n) __________________ circuit has no current flowing through it.
8. The switching device in the ignition system is the ________________.
9. There are two types of spark plugs. A ___________ spark plug dissipates heat easily,
whereas a ___________ spark plug does not dissipate heat easily.
10. Most small engines are made out of a metal called __________________. However, the
cylinder wall is usually a sleeve of ___________________.
C. Label the Diagram
On the next page, you will find a cutaway diagram of a small engine (not unlike the handout
I gave out). Please label parts #1 – 14 on the diagram.