SMALL ENGINES II Leader s Resource
This project manual is a joint effort of the P.E.I. 4-H Council and the P.E.I. Department of Agriculture reprinted 2010 This is just a guide for leaders to follow. You may do lessons as outlined in this book, or teach the project how you choose to teach it, as long as the Achievement Day Requirements have been met. It is suggested that each project have a minimum of 6 meetings to complete. Please note: The first eight pages of this guide is the Member s Guide. Each member should have a copy of the 8 page Member s Guide.
SMALL ENGINES - VOLUME TWO MAINTENANCE AND REPAIR The purpose of this project is to help 4-H members learn how to operate an engine on maximum power and efficiency. It will increase their knowledge beyond servicing and operating an engine into major maintenance and repair. It will explain the operating principles of different units such as starters, ignition systems, valves, and lubrication systems. It will also explain when these units are not operating properly and how to repair them. Each member will be required to do the following in order to successfully complete his or her project. 1. Select one small engine and work with it throughout the year. The machines or equipment, powered by small engines, that the member selects must be from the following list: - lawn mower - chain saw - snow blower - rotary tiller - power bicycle - snowmobile - motorcycle - sump pump - go-cart - dirt bike - generator 2. Complete Lessons 3. Complete Achievement Day Requirements see members guide 4. Complete a Communications Project 5. Complete a Community Project 6. Complete an Agriculture Awareness Project 1
SMALL ENGINES VOLUME TWO Achievement Day Requirements 1. Display the small engine your group worked 50 on during the year. It must be cleaned and prepared for winter storage. 2. Demonstration on one of the following three 30 topics: - Maintaining the carburetor - Maintaining the starter - Maintaining the generator 3. Leader s Test on Diagnosing Problems 20 in a Two Stroke Engine 100 EXHIBITION REQUIREMENT Small engine you and/or your group worked on during the year. It must be cleaned and prepared for winter storage. 2
LESSON ONE Each member is to select an engine, one which they will work on for the remaining project year. Be sure to select an engine that can be transported to meetings when necessary. In this lesson, the principle of good workmanship will be reviewed. Members should become familiar with the questions asked on the Owner s Engine Information Form. 3
OWNER S ENGINE INFORMATION FORM General Information Name of Equipment on which engine is mounted Name and Address of Equipment Manufacturer Name and Address of Engine Manufacturer Operating Position of Crankshaft: 9 Vertical 9 Horizontal 9 Multi-position Engine Cycle: 9 2-Cycle 9 4-Cycle Model Number or Name Serial Number Specification Number Type Number Horsepower Types of Accessories and Major Units: Carburetor Air Cleaner: Ignition System: 9 Flywheel magneto 9 Oil bath; 9 Oiled filter; 9 Dry filter 9 Flywheel magneto; 9 External magnet Fuel Strainer: 9 Combination screen and sediment bowl; 9 Screen inside the fuel tank Fuel Pump: 9 Mechanically driven; 9 Differential pressure driven Crankcase Breather:9 Reed Valve; Carburetor: 9 Float; 9 Suction Lift; 9 Floating Disk Valve 9 Diaphragm Starter: 9 Rope-wind; 9 Wind-Up; 9 Electric; 9 Electric, AC; 9 Electric, DC Governor: 9 Air Vane; 9 Centrifugal Service and Maintenance Specifications: Oil: 9 SAE 5W; 9 add 5W - 20; 9 5W - 30 Type of Spark Plug: 9 10W-30; 9 10W-40; 9 classification: SC; 9 Gap setting: 0.5 mm.020 in; 9 0.6 mm.025 in 9 or SD; 9 SE; 9 CC; 9 2-cycle Ignition Breaker-Point Gap: 9 03. mm.012 in; 9 0.4 mm.015 in; 9 Other 4
LESSON TWO - REPAIRING STARTERS 1. Check your list of tools and materials needed. 2. Your leader will be covering information on: a Repairing rope-wind starters b Repairing rope-rewind starters c Repairing windup starters 3. Discuss with your members any problems they may have in filling out the Owner s Engine Information Form. pull handle a Vertical pull rope b a horizontal rope-rewind starter b vertical pull rope-rewind starter c windup starter 5
Tools and Materials Needed Check / ROPE-Wind 1 Pocket knife or diagonal cutting pliers 2 Replacement rope 3 Matches ROPE-Rewind 1 Vice-grip pliers or adjustable end-wrench depending on your type of starter 2 Wire Paper Clip 3 Slot-head screwdriver - 8" 4 Nut driver 7/16" 5 Long nose pliers - 7" 6 Phillips head screwdriver 7 Vise - 4" 8 8 - inch c-clamps 2 9 3/4" x 3" x 5" woodstock 10 Small amount of multi-purpose grease 11 Matches 12 Rope 13 Gloves 14 Petroleum solvent mineral spirits, kerosene or diesel fuel Windup 1 Vise 4" jaws 2 8 inch clamps 2 3 Slot-head screwdriver 8" 4 Open-end wrenches 7/16", ½", 9/16" 5 Needle-nose pliers 7" 6 Combination pliers 7" 7 Multi-purpose grease A fire extinguisher is also desirable in case of fire. It should be of the dry-chemical, carbon dioxide, or foam type to be effective for gasoline or other petroleum type fires. 7
LESSON THREE REPAIRING STARTING AND GENERATING SYSTEMS 1 2 Check your list of tools and materials needed. Material covered in this lesson includes: a 120 V AC starters b Starting and generating systems Tools and Materials Needed 1 2 3 4 5 6 7 8 9 0-24 range DC Voltmeter 0-30 range ammeter 0-50 range AC Voltmeter slot-head screwdriver 8" Open-end wrenches 7/16", ½", 9/16" Brush-seating stone or sandpaper no.00 A small wooden block with a ½ square end A clean cloth Tachometer Petroleum solvent mineral spirits, kerosene or diesel fuel Battery Cutout Relay Regulator Figure: Diagram of a tractor type, starter, generator system used on small engines, showing the current voltage regulator circuit.
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LESSON FOUR - MAINTAINING AND REPAIRING IGNITION SYSTEMS 1 Check your list of tools and materials needed. 2 Material covered in this lesson includes: a Magnet and solid state ignition systems b Battery ignition systems Tools and Materials Needed 1 Socket wrench set - 1/4" through 13/16" - 3/8" drive 2 Flywheel puller 3 3 Open-end wrenches 1/4" through ½" 4 Slot-head screwdriver 6" 5 Phillips-head screwdriver 6" 6 Needle-nose pliers 7" 7 Tag-card stock or postal card for measuring air gap 8 Ignition tools 9 Feeler gage 10 Permeate, for sealing around spark-plug wire at the coil 11 Ohmmeter 12 Flywheel holder 13 Coil tester 14 Continuity test light 15 Neon timing light 16 Clean rags 17 Cleaning solvent, denatured alcohol, mineral spirits, kerosene, or diesel fuel 9
LESSON FIVE 1 Check your list of tools and materials needed. 2 Materials covered in this lesson: a Repairing fuel systems b Repairing generators Tools and Materials Needed 1 Open end wrenches 7/16" through 9/16" 2 Slot-head screwdriver 6" regular 3 Clean rags 4 Petroleum solvent mineral spirits, kerosene or diesel fuel 5 One-foot length of wire - approximately 14 gage 6 Fuel container 7 Phillips-head screwdriver 6" 8 Wire brush 9 Open-end wrenches 1/4" through ½" 10 Needle-nose pliers 7" 11 Combination pliers 7" 10
LESSON SIX - REPAIRING VALVES 1 Check your list of tools and materials needed. 2 Materials covered in this lesson: a Repairing valves on 4 cycle engine b Repairing valves on 2 cycle engine Tools and Materials Needed 1 Socket wrenches 1/4" through 9/16" 2 Wire Brush 3 Valve spring compressor 4 Valve lapping tool 5 Valve seat insert remover 6 Valve grinder 7 Feeler gage 8 Torque wrench and socket set 3/8" through 9/16" 3/8" drive and a 3/4" or 11/16" spark-plug socket 9 Slot-head screwdriver 6" regular 10 Phillips-head screwdriver 6" 11 Air pressure gage - 0 to 100 psi 12 Air operating valve adapter 13 Pocket knife 14 Micrometer 0" to 2" and 0" to 6" 15 Clean rags 16 Emery Cloth 17 Open-end wrenches 3/8" to 9/16" 18 Steel ruler 19 Punch 5/16" 20 Carburetor cleaning solvent 21 Wooden scraper 12
LESSON SEVEN - REPAIRING CYLINDERS AND PISTON-AND-ROD ASSEMBLIES 1 Check your list of tools and materials needed. 2 Material covered in this lesson: a Checking piston and piston-and-rod assembly b Repairing pistons, rods and rings c Repairing cylinders Tools and Materials Needed 1 Long-nose pliers 7" 2 Piston ring expander 3 Reamer for piston pin 4 Micrometer outside and inside 5 Ring-groove gage 6 Open-end wrenches 3/8" through 9/16" 7 Sockets, ratchet handle 3/8" through 9/16", 3/8" drive 8 Brass punch ½" x 6" 9 Piston solvent - John Deere, Stoddard or equivalent 10 Clean rags 11 Crankcase oil 12 Inside micrometer or cylinder gage 13 Home and/or boring bar coarse and find honing stones 14 Cleaning solvent mineral spirits, kerosene or diesel fuel 15 Soap and water 16 Paper and pencil 17 Cutting fluid 13
LESSON EIGHT REPAIRING LUBRICATING MECHANISMS IN 4-CYCLE ENGINES 1 2 Check your list of tools and materials needed. Material covered in this lesson: a Repairing lubricating mechanisms in 4-cycle engines Tools and Materials Needed 1 Open-end wrenches 3/8" - 9/16" 2 Slot-head screwdrivers 6" 3 Phillips-head screwdriver 6" 4 Crankcase Oil 5 Squirt can 6 Clean rags 7 Petroleum solvent mineral spirits, kerosene or diesel fuel Types of oil distribution mechanisms used on 4-cycle engines: a dipper on rod-bearing cap picks up oil and slings it over the crankcase. A pump is also supplied with this engine to maintain an oil level in the dipper trough. b A scoop on the cam gear. c A rotary oil slinger driven from the cam gear. d Gear-type pump driven from the cam gear. e Barrel-and-plunger type of pump operated from an eccentric drive located on the camshaft. 14
LESSON NINE 1 Check your list of tools and materials needed. 2 Cover information on: a Repairing camshaft assemblies in 4-cycle engines Tools and Materials Needed 1 Open-end wrenches 3/8" through 9/16" 2 Socket wrenches and handle 3/8" through 3/4" - 3/8" drive 3 Slot-head screwdriver 6" 4 Phillips-head screwdriver 6" 5 Combination pliers 7" 6 Needle-nose pliers 7" 7 Micrometer - ½" to 1" 8 Petroleum solvent mineral spirits, kerosene, or diesel fuel 9 Clean rags The primary function of the camshaft assembly is to open and close the valves at exactly the right time. a intake stroke - cam pushes tappet against the valve stem and forces the intake valve open. There is no cam action against the exhaust valve tappet in this stroke. It remains closed. b Compression stroke - no cam action against either valve tappet. Both valves are closed. c Power stroke- both valves remain closed. d Exhaust stroke - cam pushes tappet against exhaust valve stem and opens the exhaust valve. 15
LESSON TEN 1 Check list of tools and materials needed. 2 Your leader will be covering information on: a Repairing crankshaft assemblies Tools and Materials Needed 1 Long-nose pliers 7" 2 Slot-head screwdrivers 8" 3 End wrenches 3/8" through 3/4" 4 Clean rags 5 Micrometer, inside and outside 6 Arbor Press 7 Bearing puller 8 Petroleum solvent 9 Emery cloth 10 Gasket cement 11 Gaskets Checking and correcting crankshaft endplay. a Checking the crankshaft endplay with a dial indicator. b Checking the crankshaft endplay with a feeler gage. c One method for correcting crankshaft endplay is by inserting gaskets under the stator plate. 16
Volume 2 QUESTION SHEET 17
SMALL ENGINES II QUESTION SHEET 1. Several advantages were given for correctly maintaining and repairing your small engine. Name two. 2. What are two things you can do to insure that you reassemble parts of your engine correctly after working on it? 3. What are 3 types of manual starters? 4. Name 3 reasons why the rope might not rewind on a rope rewind starter. 5. Some wind-up starters have reduction gears. What is the purpose of such gears? 6. In the case of a faulty wind-up starter, the starter engages the flywheel cup but doesn t crank the engine fast enough for starting. What 2 things might be wrong? 7. After the engine has started and the starter is off, at what r.p.m. will current be generated by the generator? 8. What is an AMMETER used for when checking the generator? 9. How can you tell if a DC starter or generator has been overheated? 10. What are 2 essential requirements of a spark in spark ignition engine? 11. Magnetos generate electricity. The amount of current flow is determined by what 3 conditions? 12. How is the amount of voltage induced in the secondary coil related to the number of turns in the primary and secondary coils of the transformer? Give an example using numbers. 13. What is the starter-plate air gap? What is its importance? 14. In what two main ways does a battery ignition system differ from the magnetoignition system? 15. Your carburetor may require adjustment. A too rich fuel-air mixture is causing knock, loss of power, scoring and scuffing of cylinder and piston walls. What causes this damage? 16. Name the 5 principal parts of the fuel system. 17. Why is a vent necessary in a fuel tank? Where is it usually located? 18. The prevents an engine from both overspeeding and underspeeding. 18
19. What will poor float adjustment or a stuck float valve in the carburetor usually result in? 20. Name 3 faulty valve conditions in 4-cycle engines. 21. What is a very common cause of intake valve problems? 22. When installing the cylinder head, why is it important to tighten the cap screws in the recommended sequence and with the proper torque? 23. Pistons are grooved for rings. Name 3 types of rings usually found on a 4-cycle engine. 24. What is the purpose of lapping valves? 25. Where does most wear occur on cylinders? 26. When checking the cylinders, why should you measure the cylinder diameter 3 reasons? 27. What is a hone used for? 28. What is the main function of the camshaft assembly in a 4-cycle engine? 29. Name 3 important functions of the crankshaft assembly. 30. What is the importance of endplay with regards to the crankshaft? 19
SMALL ENGINES II _ Answer Sheet 1. a b 2. a b 3. a b c 4. a b c d 5. 6. a b 7. 8. 9. 10. a b 11. a b c 12. 13. 14. a b 15. 20
16. a b c d e 17. 18. 19. 20. a b c 21. 22. 23. a b c 24. 25. 26. a b c 27. 28. 29. a b c 30. 21