Course Title:
Small Engine Technology
Lesson Title:
Disassembly of the Small Engine
TEKS Addressed in Lesson: 130.400 http://ritter.tea.state.tx.us/rules/tac/chapter130/ch130p.html
130.400c8A
130.400c8C
130.400c8F
130.400c8G
The student describes the historical, current, and future significance of the small engine technology
industry: The student will define terms associated with the small engine technology industry.
The student demonstrates the technical knowledge and skills for small engine technology:
The student will identify the use and application of small engines and components; demonstrate knowledge
of small engine designs, components, and applications; discuss the characteristics of two- and four-cycle
engines; and identify the major engine components and their functions.
Lesson Objectives. The student will be able to:
1. Determine the appropriate repair manual for the task to be performed;
2. Determine engine specifications and adjustments using repair manuals and service bulletins; and
3. Interpret exploded assembly views in repair manuals and service bulletins.
Tools and Equipment
Dry-erase board or flip chart & markers
PowerPoint slides – laptop and LCD projector
Computer with Internet access, if available
Teaching Aids: Small engine, models, mock-ups
PowerPoint Slides: VI-D-15(PP) Figures 1-12
Information Sheet, VI-D-15(IS) "Disassembly of the Small Engine"
Assignment Sheet, VI-D-15(AS) "Disassembly of the Small Engine"
Key Terms / Vocabulary
Compression rings
Connecting rod
Connecting rod bolt
Oil ring
Piston
Piston pin
Piston ring expander
Retainer ring
Self-locking nut
Washer
Collars
Face
Head
Lock groove
Margin
Neck
Pin
Retainer
Spring
Stem
Air cleaner
Carburetor
Choke lever
Cylinder head
Drain plug
Fuel filter
Fuel line
Fuel tank
Fuel valve
Governor screw
Idle screw
Idle valve
Needle valve
Oil drain plug
Oil filler plug
Oil sump
Power shaft
Spark plug
Stop switch
Interest Approach / Anticipatory Set
Preventive maintenance is the key to extended life of small gasoline engines. Maintenance practices such as
periodic oil level checks, spark plug inspection, keeping the engine clean, and changing oil as recommended
by the service manual are necessary for long engine life. Normal wear will eventually lead to replacement of
parts or even a complete overhaul. Small engines may be reconditioned at a reasonable cost if proper tools
are available and if the operator possesses special skills. In some cases it may be more economical to buy a
new engine than to pay for a complete overhaul.
As a small engine mechanic, you will have to be able to disassemble the engine. In this lesson, we will
discuss some of the common procedures used.
Teaching Plan and Strategy / Presentation of New Material
1. Discuss the procedures used for engine cleaning.
Show Slide Figure #1
2. Present the preliminary steps in disassembly.
3. Illustrate disassembly of the main body.
Show Slide Figure #2
Show Slide Figure #3
Show Slide Figure #4
Show Slide Figure #5
Show Slide Figure #6
4. Discuss valve removal.
Show Slide Figure #7
5. Discuss camshaft removal.
Show Slide Figure #8
6. Explain inspection and measurement procedures.
Show Slide Figure #9
7. Note the inspection points on the small engine.
Activity / Application / Student Engagement / Laboratory
Reading Assignment:
Information Sheet, VI-D-15(IS) "Disassembly of the Small Engine"
Written Assignment:
Assignment Sheet, VI-D-15(AS) "Disassembly of the Small Engine"
Call on students to complete the following statements.
operator's manual
1. The ______ ______ for each small engine has specifications and instructions
that should be followed in servicing and repairing the engine.
internal
2. Loose dirt and other foreign material should be blown off the engine with
compressed air, but care should be taken not to get dirt into the engine's
______ parts.
discarded
3. Oil that is drained from the oil bath air cleaner and the crankcase should be
_______ .
fuel tank
4. If the engine has a suction type carburetor system, remove the ______
______ and carburetor together.
replaced
5. The muffler can be left attached to the engine, unless it is to be ______ .
solvent
6. Carburetor parts should be cleaned with a gum ______ or lacquer thinner.
new
7. Gaskets should be ______ when reassembling the carburetor.
piston ring expander
8. Use a ______ ______ ______ to remove the rings from the piston.
compressor
9. Valves are easier to remove if a valve-spring ______ is used to press the
springs before trying to remove the valve retainer.
scraper groove
10. When installing rings, the center compression ring should be installed with
the ______ ______ down.
Evaluation / Summary
Show Slide Figure #10. Have students identify the external parts of the 4-cycle small engine.
1. Stop switch
11. Oil drain plug
2. Spark plug
12. Oil sump
3. Governor screw
13. Power shaft
4. Air cleaner
14. Fuel line
5. Idle screw
15. Fuel valve
6. Idle valve
16. Fuel filter
7. Choke lever
17. Drain plug
8. Carburetor
18. Cylinder head
9. Needle valve
19. Fuel tank
10. Oil filler plug
Show Slide Figure #11. Have students identify the parts of the valve assembly.
1. Head
6.
Stem
2. Retainer
7.
Spring
3. Pin
8.
Neck
4. Collars
9.
Face
5. Lock groove
10. Margin
Show Slide Figure #12. Have students identify the parts of the piston assembly.
1. Piston
6.
Self-locking nut
2. Piston pin
7.
Connecting rod
3. Retainer ring
8.
Oil ring
4. Connecting rod bolt
9.
Compression rings
5. Washer
Briefly review the following topics:
A. Engine Cleaning
B. Preliminary Steps in Disassembly
C. Disassembly of the Main Body
D. Measurements
E. Inspection Points
References / Additional Materials / Extended Learning Opportunities / Enrichment
Chain Saw Service Manual
http://www.chainsawsdirect.com/stories/404-How-to-Access-Old-Chain-Saw-Manuals.html
http://lawnandgarden.manualsonline.com/manuals/device/chainsaw.html
http://www.stihlusa.com/manuals/instruction-manuals/
http://www.oregonproducts.com/pro/pdf/maintenance_manual/ms_manual.pdf
Grounds Keeping Equipment
http://www.salsco.com/products/landscaping-equipment-2.html
http://www.nationalipa.org/toro.html
http://www.countrylawn-garden.com/
Small Engines Service Manual
http://www.briggsandstratton.com/us/en/shop/learning-resources
http://www.haynes.com/products/sfID1/3/sfID2/35/sfID3/24
http://home.howstuffworks.com/home-improvement/repair/how-to-repair-small-engines.htm
http://engines.honda.com/parts-and-support/service-support
http://www.repairclinic.com/RepairHelp/small-engine-Repair-Help
http://www.amazon.com/s/?ie=UTF8&keywords=small+engine+service+manual&tag=googhydr20&index=aps&hvadid=26647482847&hvpos=1t1&hvexid=&hvnetw=g&hvrand=12382183683580208753&h
vpone=&hvptwo=&hvqmt=e&hvdev=c&ref=pd_sl_8zcs6a9n77_e
College & Career Readiness Standards: http://www.thecb.state.tx.us/collegereadiness/crs.pdf
ENGLISH/LANGUAGE ARTS STANDARDS
I. Writing – A 2
II. Reading – A 1 2 3 4 5 8 11 B 1 2 3
III. Speaking – A 1 2 B 1 2 3
IV. Listening – A 1 2 3 B 1 2 3
V. Research – 2 B 1 2
MATHEMATICS STANDARDS
IV. Measurement Reasoning – A 1 B 1 2
SCIENCE STANDARDS
I. Nature of Science: Scientific Ways of Learning and Thinking – C 1 2 3
III. Foundation Skills: Scientific Applications of Communication – A 1 B 1 2 3 D 1 2
VIII. Physics – A 2 3 4 5 C 1 2 3 D 1 2 3 E 1 2 3 4 F 1 2 3 4 H 1 2 I 1 2 3 4 5 6 7 8
X. Environmental Science – E 5
SOCIAL STUDIES STANDARDS
IV. Analysis Synthesis and Evaluation of Information – C 1 D 1 2
V. Effective Communication – A 1 2 B 1
CROSS-DISCIPLINARY STANDARDS
I. Key Cognitive Skills – A 1 2 C 1 2 3 D 1 2 3 4 E 1 2 F 1 2 3 4
II. Foundational Skills – A 1 2 3 4 5 6 7 8 B 1 2 C 1 2 3 4 5 6 7 8 E 1 2 3 4
Revised by:
CDC Custom Development Co., LLC
for Texas A&M University.
Copyright © 2014 Texas Education Agency