SGE FINAL REVIEW

BELLWORK 3/7/12

Write 6 questions that you could possibly see on the small gas engines final exam.

-2 Multiple Choice Questions

-2 T/F Questions

-2 Fill in the Blank Questions

DO NOT ANSWER YOUR QUESTIONS!

SHOP SAFETY• Classes of Fires

• Class A fires—involve combustible materials like wood, paper, cloth, plastics, or other materials that may be considered flammable.

• Class B fires—involve flammable liquids such as gasoline, solvents, oil, grease, oil-based paints, paint thinners, etc.

• Class C fires—involve electricity in objects such as motors, generators, transformers, or switch panels.

• Class D fires—involve certain combustible metals and chemicals such as magnesium, titanium, sodium, etc.

1. Red – Designates the location of fire equipment, the stop button of electrical equipment,

and acetylene lines and acetylene carts

2. Red with yellow letters - Indicates gasoline can

3. Orange - Designates guards, electrical control boxes, and hazardous areas

4. Yellow - Designates adjustment wheels, knobs, levers, and safety islands

5. Yellow with diagonal black stripes - Designates areas where you might stumble, fall, or strike against a hazardous object

6. Blue - Designates large electrical panels or boxes and Out of Order signs

7. Green - Indicates medicine, first aid supplies, oxygen lines, and carts

8. Ivory - Designates edges of tables and equipment

9. Aluminum-black band - Indicates waste container

10. Aluminum-orange band - Designates container for oily rags and flammable materials

11. Gray - Indicates cleanup area

SMALL GAS ENGINES IN USE• Common uses of Small Gas Engines:

• Lawn mowers• Snowblowers• Chainsaws• Air compressors

• Major Manufacturers of Small Gas Engines

• Briggs and Stratton• Tecumseh• Clinton• Kohler• Lawn Boy

Advantages of Small Gas Engines:

• Inexpensive to purchase

• Inexpensive to operate

• Portable

• Compact

• Light in weight

• Air cooled

• Self-contained

• Easy to service

Disadvantages of Small Gas Engines:

• Hard to start

• Wear out fast

• Not very sophisticated (low efficiency)

FUNCTIONS OF OIL4 Functions of Oil:

1. Lubrication

2. Cooling

3. Sealing

4. Cleaning

Oil Suitable for SGE:

• The S means that the oil is intended for use in engines with a spark ignition such as gasoline engines.

Lack of Lubrication can cause an engine to:

• Run unevenly

• Spin freely

• Lack Power

ENGINE SYSTEMSThe air filter belongs to the FUEL system.

-Includes fuel tank, fuel lines, carburetor and intake system.

-Carburetor provides fuel and air to the engine in appropriate proportions and volume to ignite and burn efficiently.

-An air filter mounted at the opening of the carburetor cleans air before it enters the engine.

Parts of the Carburetor:

-Air Filter

-Gasket to make carburetor and carburetor/engine mounting airtight

-Throttle and choke plates

**FUEL is the main source of problem in carburetors**

Improper Carburetor Adjustment can cause an engine to:

• Overheat

• Fail to Start

• Lack of Power

ENGINE MEASUREMENTS

Horsepower-- The power of one horse.

hp = L X W

33,000 X t

hp = torque X RPM

5252

Power-- The amount of work that is done in a period of time.

Power=Work/Time

Compression Ratio--

The measure of how much the air/fuel mixture is compressed in an engine cylinder.

BDC/TDC : 1

AIR FILTERS

• Foam element which uses oil to assist in trapping dirt.

• Paper cartridge type which relies upon a great surface area and small pore sizes to trap dirt.

• Dual element - a paper cartridge element surrounded by an oil-foam pre-cleaner element which uses the benefits of each type.

FUEL IN SMALL GAS ENGINES

Fuel can stay fresh in a small gas engine for 30 days or 1 month.

About one gallon of water is produced for every gallon of gasoline burned.

When an engine operates normally at temperature, this water escapes as steam.

When the engine is cold, some water is trapped in the oil, and helps to form sludge.

POWER IN SGE

• During the operation of an engine, it is normal for it to accumulate deposits of carbon in the combustion chamber.

• Excessive carbon will result in a loss of power, and shorten value life.

• Every 100 to 300 hours, you should remove the cylinder head, set the piston at top dead center with both valves closed, and clean the cylinder head of these deposits.

• Install a new plug, new head gasket, and torque the head bolts according to the manual, and you have performed a power tune-up.

SPARKPLUG MAINTENANCE

-The spark plug must maintain at least .030 inches of gap.

-Every 100 hours, remove plug, clean it, and reset gap.

-The plug should be replaced annually, and preferably every 100 hours.

HEADGASKETS

The head gasket is compressed between the head and the block, and it must seal and contain the pressure of the explosion of the fuel air mixture.

FUNDAMENTAL OPERATING REQUIREMENTS OF SMALL ENGINES• Air must be able to flow across the fins under the blower

housing.

• Any trash or debris will create hot spots in the engine.

• Clean the finger guard, rotating screen and exposed fins daily, or more often as needed. At each refueling it would be a good idea to look at them.

• Keep trash and debris out of throttle linkages and govern linkage. Clean and inspect them each day of use.

• Before starting engine, clean muffler of any combustible debris. Keep it clean as needed.

• If the muffler has a spark arrestor screen, remove it and clean it every 50 hours.

• Dirt and debris can enter the block housing with cooling air and block the fins. Every 100 hours of use or once a season, remove the block housing and clean the cooling fins.