xvii
C H A P T E R 9
Carburetion and
Fuel Injection. . . . . . . . . . . . . 159
Principles of Carburetion . . . . . . . . . . 159
Air-Fuel Mixture . . . . . . . . . . . . . . . . . . . . . . . .160
Carburetor Pressure Differences. . . . . . . . . . .160
Types of Carburetors . . . . . . . . . . . . . 162
Float-Type Carburetors . . . . . . . . . . . . . . . . . .163
Diaphragm-Type Carburetors. . . . . . . . . . . . .168
Vacuum Carburetors . . . . . . . . . . . . . . . . . . . .171
Primers. . . . . . . . . . . . . . . . . . . . . . . . . 172
Anti-Afterfire Solenoids . . . . . . . . . . . 172
Manual Throttle Controls . . . . . . . . . . 173
Governor Throttle Controls . . . . . . . . 174
What an Engine Governor Does. . . . . . . . . . .174
Types of Governors. . . . . . . . . . . . . . . . . . . . . .175
Governor Features . . . . . . . . . . . . . . . . . . . . . .178
Introduction to Electronic
Fuel Injection (EFI) . . . . . . . . . . . . . . . 179
Open-Loop and Closed-Loop EFI Systems . . .180
Advantages of EFI . . . . . . . . . . . . . . . . . . . . . .180
EFI System Components . . . . . . . . . . 181
Fuel Pump and Fuel Pressure Regulator. . . .182
Fuel Injector. . . . . . . . . . . . . . . . . . . . . . . . . . . .182
Throttle Body. . . . . . . . . . . . . . . . . . . . . . . . . . .182
Engine Control Unit (ECU) . . . . . . . . . . . . . . .183
Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183
Idle Air Control Valve . . . . . . . . . . . . . . . . . . .184
C H A P T E R 1 0
Ignition Systems. . . . . . . . . . 189
Basic Ignition System Operation. . . . 189
Ignition System Components . . . . . . 191
Ignition Coil. . . . . . . . . . . . . . . . . . . . . . . . . . . .191
Spark Plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . .191
Spark Plug Wire . . . . . . . . . . . . . . . . . . . . . . . .192
Switching Devices. . . . . . . . . . . . . . . . . . . . . . .192
Magneto Ignition Systems . . . . . . . . . 194
Operation of Capacitive
Discharge Ignition (CDI) System . . . . . . .195
Operation of Transistor-Controlled
Ignition (TCI) System . . . . . . . . . . . . . . . . .196
Operation of the Mechanical
Breaker Point Ignition (MBI) System . . . .199
Magneto Ignition Systems
for Two-Cylinder Engines . . . . . . . . . . . . .201
Battery Ignition Systems . . . . . . . . . . 201
Ignition Coil. . . . . . . . . . . . . . . . . . . . . . . . . . . .202
Lead-Acid Battery. . . . . . . . . . . . . . . . . . . . . . .203
The Discharging/Charging Cycle . . . . . . . . .204
C H A P T E R 1 1
Lubrication Systems . . . . . . 207
Principles of Lubrication . . . . . . . . . . 207
Friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .207
Qualities of Lubricating Oil . . . . . . . . 208
Permits Easy Starting . . . . . . . . . . . . . . . . . . . .208
Lubricates and Prevents Wear . . . . . . . . . . . .208
Protects Against Rust and Corrosion. . . . . . .209
Keeps Engine Parts Clean . . . . . . . . . . . . . . . .209
Cools Engine Parts . . . . . . . . . . . . . . . . . . . . . .210
Seals Combustion Pressures . . . . . . . . . . . . . .210
Prevents Foaming . . . . . . . . . . . . . . . . . . . . . . .210
Aids Fuel Economy . . . . . . . . . . . . . . . . . . . . .210
Oil Specifications . . . . . . . . . . . . . . . . 210
SAE Viscosity Grade. . . . . . . . . . . . . . . . . . . . .210
API Engine Oil Service Classifi cation . . . . . .211
Selecting the Proper Engine Oil . . . . 212
Engine Lubrication Systems . . . . . . . 213
Two-Cycle Engine Lubrication . . . . . . . . . . . .213
Four-Cycle Engine Lubrication. . . . . . . . . . . .214
Oil Filter Systems . . . . . . . . . . . . . . . . . . . . . . .216
Low-Oil Warning and
Shutdown Systems (LOS) . . . . . . . . . . . . .218
C H A P T E R 1 2
Cooling Systems. . . . . . . . . . 223
Principles of Engine Cooling. . . . . . . 223
Air Cooling. . . . . . . . . . . . . . . . . . . . . . 224
Liquid Cooling. . . . . . . . . . . . . . . . . . . 225
Pressurized Cooling Systems . . . . . . . . . . . . .225
Outboard Engine Cooling Systems . . . . . . . .227
Copyright Goodheart-Willcox Co., Inc.