1988 JOHNSON EVINRUDE 20HP OUTBOARD Factory Service & Work Shop Manual

U DO IT DATA©

TABLE OF CONTENTS 1 SAFETY INTRODUCTION CLEANING, WAXING, AND POLISHING CONTROLLING CORROSION PROPELLERS FUEL SYSTEM LOADING HORSEPOWER FLOTATION EMERGENCY EQUIPMENT COMPASS STEERING ANCHORS MISCELLANEOUS EQUIPMENT BOATING ACCIDENT REPORTS NAVIGATION 2 TUNING INTRODUCTION TUNE- UP SEQUENCE COMPRESSION CHECK SPARK PLUG INSPECTION IGNITION SYSTEM SYNCHRONIZING BATTERY SERVICE CARBURETOR ADJUSTMENTS FUEL PUMPS STARTER AND SOLENOID INTERNAL WIRING HARNESS WATER PUMP CHECK PROPELLER LOWER UNIT BOAT TESTING INTRODUCTION Theory of Operation CHAPTER ORGANIZATION POWERHEAD DISASSEMBLING HEAD SERVICE REED SERVICE Description Reed Valve Adjustment Cleaning and Service BYPASS COVERS EXHAUST COVER Cleaning TOP SEAL Removal BOTTOM SEAL Inspec tion CENTERING PINS MAIN BEARING BOLTS AND CRANKCASE SIDE BOLTS 3- 15 CRANKCASE COVER 3- 16 Removal 3- 16 Cleaning and Inspecting 3-16 CONNECTING RODS AND PISTONS 3- 16 Removal 3-17 Disassembly 3- 18 Rod Inspection and Service 3-21 Piston and Wing Inspection and Service 3-22 Assembling 3-24 CRANKSHAFT 3-27 Removal 3-27 Cleaning and Inspection 3-27 Assembling 3- 28 CYLINDER BLOCK SERVICE 3- 28 Honing Procedures 3-29 Assembling 3-30 Piston and Rod Assembly Inst allat ion 3-30 Crankshaft Installation Large Horsepower Engines 15 hp to 40 hp 3- 33 Crankshaft Installation Small Horsepower Engines 1.5 hp, 5.0 hp, 5.5 hp, 6.0 hp, 9.5 hp 3-35 Crankshaft Installation Small Horsepower Engines 3.0 hp, 4.0 hp, 7.5 hp 3-37 Crankcase Cover Installation 3- 38 Main Bearing Bolt and Crankcase Side Bolt Installation 3-39 Bottom Seal Installation 15 hp to 40 hp Engines 3- 39 Exhaust Cover and Bypass Cover Installation 3-40 Reed Box Installation 3-40 Head Installation 3-41 BREAK- IN PROCEDURES 3-41 EXPLODED DRAWINGS 3-42 - 3-50 U DO IT DATA©

4 FUEL INTRODUCTION GENERAL CARBURETION INFORMATION FUEL SYSTEM TROUBLESHOOTING Fuel Pump Tests Fuel Line Test Testing with Pressure Tank Rough Engine Idle Excessive Fuel Consumption CARBURETORS TYPE I CARBURETOR Removal and Disassembling Cleaning and Inspecting Assembling CHOKE SYSTEM SERVICE HeatIElectric Choke All Electric Choke Water Choke TYPE I1 CARBURETOR Disassembling Cleaning and Inspecting Assembling ASSEMBLING CHOKES TO TYPE 11 CARBURETORS Adjustments TYPE 111 CARBURETORS Removal Cleaning and Inspecting Assembling Adjustments FUEL PUMP SERVICE Troubleshooting Removal and Repair Cleaning and Inspecting Assembling and Installation FUEL TANK AND LINE SERVIC Disassembling Cleaning and Inspecting Assembling LATE MODEL FUEL TANK SERVICE 5 IGNITION INTRODUCTION 5- 1 SPARK PLUG EVALUATION 5-2 POLARITY CHECK 5- 3 WIRING HARNESS 5-4 FLYWHEEL MAGNETO IGNITION 5-5 TROUBLESHOOTING 5-6 SERVICING FLYWHEEL MAGNETO IGNITION SYSTEM 5- 13 Removal 5- 13 Cleaning and Inspecting 5- 19 Assembling 5-20 SYNCHRONIZATION FUEL AND IGNITION SYSTEMS 5- 26 Primary Pickup Adjustments and Locations 5- 26 6 ELECTRICAL INTRODUCTION 6- 1 BATTERIES 6-1 Marine Batteries 6-1 Battery Construction 6-2 Battery Location 6-2 Battery Service 6-2 Jumper Cables 6-5 Dual Battery Installation 6-5 GAUGES AND HORNS 6-7 Constant - Voltage System 6-7 SERVICE PROCEDURES 6-7 Temper at ure Gauges 6-7 Warning Lights Thermomelt Sticks 6-8 FUEL SYSTEM 6-8 Fuel Gauge 6-8 Fuel Gauge Hookup 6-8 Troubleshooting 6-9 TACHOMETER 6- 10 HORNS 6-10 ELECTRICAL SYSTEM GENERAL INFORMATION 6- 11 CHARGING CIRCUIT SERVICE 6- 12 Troubles hooting 6-12 Generator Service 6-16 Armature Testing 6- 17 Cleaning and Inspecting 6- 18 Assembling 6-20 CHOKE CIRCUIT SERVICE 6-22 STARTER MOTOR CIRCUIT SERVICE 6- 22 Circuit Description 6-22 Starter Motor Description 6-22 Troubleshooting 6-24 Testing 6- 25 STARTER DRIVE GEAR SERVICE 6- 26 Starter Removal 6-26 Drive Gear Disassembling 6-27 Cleaning and Inspecting 6-27 Assembling Type I Drive 6- 28 Disassembling Type II 6- 28 Cleaning and Inspecting 6- 28 Assembling Type I1 Drive 6- 28 DEECO-REMY SERVICE 6- 29 Removal 6- 29 Disassembling 6- 29 Armature Testing 6-30 Cleaning and Inspecting 6-31 Assembling 6-32 U DO IT DATA©

6 ELECTRICAL (CONT) AUTOLITE STARTER MOTOR SERVICE Removal Disassembling Armature Testing Cleaning and Inspecting Assembling PRESTOLITE STARTER MOTOR SERVICE Removal Disassembling Armature Testing Cleaning and Inspecting Assembling STARTER MOTOR TESTING STARTER MOTOR INSTALLATION 7 ACCESSORIES INTRODUCTION 7- 1 SHIFT BOXES 7- 1 Description 7- 1 OLD- STYLE DOUBLE LEVER 7- 3 Troubleshooting 7- 3 Disassembling 7-4 Cleaning and Inspection 7- 5 Assembling 7- 5 NEW-STYLE SHIFT LEVER 7-6 Troubleshooting 7-6 Removal 7-8 Disassembling 7-8 Cleaning and Inspecting 7-9 Assembling 7- 10 ELECTRIC GEAR BOXES AND SINGLE LEVER CONTROL 7- 12 Troubleshooting 7- 12 Disassembling 7- 14 Cleaning and Inspecting 7- 15 Assembling 7- 16 PUSH BUTTON SHIFT BOX SERVICE EVINRUDE UNITS ONLY 7- 18 Troubleshooting 7- 19 Disassembling 7-21 Cleaning and Inspecting 7- 22 Assembling 7- 22 CABLE END FITTING INSTALLA- TION AT THE ENGINE END 7- 24 8 LOWER UNIT DESCRIPTION 8- 1 Chapter Coverage 8- 1 Illustrations 8- 2 TROUBLESHOOTING MANUAL SHIFT 8-2 PROPELLER REMOVAL 8-7 DRAINING LOWER UNIT LOWER UNIT SERVICE 1.5 hp to 4.0 hp -- NO SI-IIFT Lower Unit Removal Water Pump Removal Disassembling Cleaning and Inspecting Assembling Water Pump Installation Lower Unit Installation Filling the Lower Unit Propeller Installation LOWER UNIT SERVICE MANUAL SHIFT -- 5 HP TO 25 HP Removal Water Pump Removal Disassembling Cleaning and Inspecting Assembling Water Pump Installation Lower Unit Installation LOWER UNIT SERVICE MANUAL SHIFT -- 28 HP TO 40 HP 8- 36 Removal 8-37 Water Pump Removal 8- 38 Disassembling 8- 38 Cleaning and Inspecting 8- 41 Assembling 8- 46 Lower Unit Installation 8- 50 EEECTROMATIC LOWER UNIT 8- 53 Description 8- 53 Troubleshooting 8- 53 Removal 8- 56 Disassembling 8-57 Cleaning and Inspecting 8- 65 Assembling 8-66 Water Pump Installation 8-72 Lower Unit Installation 8-74 9 HAND STARTERS INTRODUCTION 9-1 Operation 9-2 TYPE I STARTER CYLINDER WITH PINION GEAR 5 HP and 6 HP ENGINES 9- 3 Starter Rope Replacement 9-4 Removal 9-4 Installation 9-4 Starter Removal 9-5 Disassembling 9-7 Cleaning and Inspecting 9-7 Assembling 9-7 - U DO IT DATA©

9 HAND STARTERS (CONTI - TYPE I STARTER CYLINDER WITH PINION GEAR ALL 9.5 HP ENGINES 9- 11 Starter Rope Replacement 9-1 1 Removal 9-1 1 Installation 9- 12 Starter Removal 9 - 12 Cleaning and Inspecting 9- 14 Assembling 9-14 Installation 9- 15 TYPE I1 STARTER COIL SPRING WITH SWING ARM DRIVE GEAR 3 HP 1968 4 HP 1969- 70 9-17 Removal 9-17 Disassembling 9-17 Cleaning and Inspecting 9-20 Assembling 9-20 TYPE I11 STARTER MOUNTED ATOP FLYWHEEL MODEL WITH RETURN SPRINGS 28 HP 1962 - 63 30 HP 1956 35 HP 1957- 59 40 HP 1960-63 9- 23 Removal 9-24 Cleaning and Inspecting 9-26 Assembling 9-27 Rope Installation 9- 29 Starter Installation 9-30 TYPE I11 STARTER MOUNTED ATOP FLYWHEEL MODEL WITH NO RETURN SPRINGS 28 HP 1964 33 HP 1965 - 70 40 HP 1964- 70 9-31 Removal 9-32 Cleaning and Inspecting 9-34 Assembling 9-34 Rope Installation 9-37 Starter Installation 9-39 TYPE I11 STARTER MOUNTED ATOP FLYWHEEL MODEL WITH ONE NYLON PAWL 3 HP 1956- 68 5.5 HP 1956- 64 7.5 HP 1956- 58 10 HP 1956- 63 15 HP 1956 18 HP 1956 - 70 20 HP 1966-70 25 HP 1969- 70 9-39 Removal 9-40 Disassembling 9-40 Cleaning and Inspecting 9-42 Assembling 9- 43 Rope Installation 9- 43 Starter Installation 9-46 10 MAINTENANCE INTRODUCTION ENGINE SERIAL NUMBERS FIBERGLASS HULLS ALUMINUM HULLS BELOW WATERLINE SERVICE SUBMERGED ENGINE SERVICE WINTER STORAGE LOWER UNIT SERVICE Propeller BATTERY STORAGE PRESEASON PREPARATION APPENDIX METRIC CONVERSION CHART A-1 DRILL SIZE CONVERSION CHART A-2 TORQUE SPECIFICATIONS A- 3 POWERHEAD SPECS A-4 & A-5 TUNE- UP SPECS A-6 to A10 GEAR OIL CAPACITIES A-11 STARTER MOTOR SPECS A-12 REGULATOR SPECS A- 12 GENERATOR SPECS A-12 CONDENSER SPECS A- 13 STARTER ROPE SPECS A-14 WIRE INDENTIFICATION DRAWINGS 20 hp and 25 hp -- 197 1-72 A-15 33 hp with Generator -- 1965- 67 A-16 33 hp with Generator -- 1968 A-17 33 hp with Generator -- 1969- 70 A- 18 35 hp -- 1957- 59 A- 19 40 hp Standard Shift with Generator -- 1960- 66 A-20 40 hp Standard Shift with Generator -- 1967- 68 A-21 40 hp Standard Shift with Generator -- 1969- 70 A-22 40 hp Electric Shift with Generator -- 1961- 66 A- 23 40 hp Electric Shift with Generator -- 1967-68 A-24 40 hp Electric Shift with Generator -- 1969- 70 A-25 U DO IT DATA©

SAFETY 1- 1 INTRODUCTION Your boat probably represents a sizeable investment for you. In order to protect this investment and to receive the maximum amount of enjoyment from your boat it must be cared for properly while being used and when it is out of the water. Always store your boat with the bow higher than the stern and be sure to remove the transom drain plug and the inner hull drain plugs. If you use any type of cover to protect your boat, plastic, canvas, whatever, be sure to allow for some movement of air through the hull. Proper ventilation will assure evaporation of any condensation that may form due to changes in temperature and humidity. 1- 2 CLEANING, WAXING, AND POLISHING An outboard boat should be washed with clear water after each use to remove sur - face dirt and any salt deposits from use in salt water. Regular rinsing will extend the time between waxing and polishing. It will also give you " pride of ownership " , by having a sharp looking piece of equipment. Elbow grease, a mild detergent, and a brush Whenever the boat is stored, for long or short periods, the bow should be slightly higher than the stern and the drain plug in the transom removed to ensure proper drainage of rain water. will be required to remove stubborn dirt, oil, and other unsightly deposits. Stay away from harsh abrasives or strong chemical cleaners. A white buffing com- pound can be used to restore the original gloss to a scratched, dull, or faded area. The finish of your boat should be thoroughly cleaned, buffed, and polished at least once each season. Take care when buffing or polishing with a marine cleaner not to over - heat the surface you are working, because you will burn it. A small outboard engine mounted on an aluminum boat should be removed from the boat and stored separately. Under all cir - cumstances, any outboard engine must AL- WAYS be stored with the powerhead higher than the lower unit and exhaust system. This position will prevent water trapped in the lower unit from draining back through the exhaust ports into the powerhead. Lower unit badly corroded because the zinc was not replaced. Once the zinc is destroyed, more costly parts will be damaged. Attention to the zinc condition is extremely important during boat operation in salt water. U DO IT DATA©

1 - 2 SAFETY A new zinc prior to installation. This inexpensive item will save corrosion on more valuable parts. Most outboard engines have a flat area on the back side of the powerhead. When the engine is placed with the flat area on the powerhead and the lower unit resting on the floor, the engine will be in the proper altitude with the powerhead higher than the lower unit. 1-3 CONTROLLING CORROSION Since man first started out on the water, corrosion on his craft has been his enemy. The first form was merely rot in the wood and then it was rust, followed by other forms of destructive corrosion in the more modern materials. One defense against cor - rosion is to use similar metals throughout the boat. Even though this is difficult to do in designing a new boat, particularily the undersides, similar metals should be used whenever and wherever possible. A second defense against corrosion is to insulate dissimilar metals. This can be done by using an exterior coating of Sea Skin or by insulating them with plastic or rubber gaskets. Using Zinc The proper amount of zinc attached to a boat is extremely important. The use of too much zinc can cause wood burning by plac - ing the metals close together and they be - come "hot". On the other hand, using too Diameter and pitch are the two basic dimensions of a propeller. The diameter is measured across the circumference of a circle scribed by the propeller blades, as shown. small a zinc plate will cause more rapid deterioration of the metal you. are trying to protect. If in doubt, consider the fact that is is far better to replace the zincs than to replace planking or other expensive metal parts from hav& an excess of zinc. When installihg zinc plates, there are two routes available. One is to install many different zincs on all metal parts and thus run the risk of wood burning. Another route, is to use one large zinc on the tran - som of the boat and then connect this zinc to every underwater metal part through internal bonding. Of the two choices, the one zinc on the transom is the better way to go* Small outboard engines have a zinc plate attached to the cavitation plate. Therefore, the zinc remains with the engine at all times. 1- 4 PROPELLERS As you know, the propeller is actually what moves the boat through the water. This is how it is done. The propeller oper - ates in water in much the manner as a wood screw does in wood. The propeller " bites' " into the water as it rotates. Water passes between the blades and out to the rear in the shape of a cone. The propeller "biting" through the water in much the same manner as a wood auger is what propels the boat. Propeller and associated parts in order, washer, shear-pin, and nut, ready for installation. U DO IT DATA©

PROPELLERS 1 - 3 Arrangement of propeller and associated parts, in order, for a small horsepower engine. Diameter and Pitch Only two dimensions of the propeller are of real interest to the boat owner: the diameter and the pitch. These two dimen - sions are stamped on the propeller hub and always appear in the same order: the diameter first and then the pitch. For instance, the number 15 - 19 stamped on the hub, would mean the propeller had a diameter of 15 inches with a pitch of 19. The diameter is the measured distance from the tip of one blade to the tip of the other as shown in the accompanying illus- tration. The pitch of a propeller is the angle at which the blades are attached to the hub. This figure is expressed in inches of water travel for each revolution of the propeller. In our example of a 15 - 19 propeller, the propeller should travel 19 inches through the water each time it revolves. If the propel - ler action was perfect and there was no slippage, then the pitch multiplied by the propeller rpms would be the boat speed. Most outboard manufacturers equip their units with a standard propeller with a diameter and pitch they consider to be best suited to the engine and the boat. Such a propeller allows the engine to run as near to the rated rpm and horsepower (at full throt - tle) as possible for the boat design. The blade area of the propeller deter - mines its load - carrying capacity. A two- blade propeller is used for high - speed run - ning under very light loads. Shear-pin installed behind the propeller instead of in front of the propeller. A four - blade propeller is installed in boats intended to operate at low speeds under very heavy loads such as tugs, barges, or large houseboats. The three - blade propeller is the happy medium covering the wide range between the high performa'nce units and the load carrying workhorses. Propeller Selection There is no standard propeller that will do the proper job in very many cases. The list of sizes and weights of boats is almost endless. This fact coupled with the many boat - engine combinations makes the propel - ler selection for a specific purpose a diffi - cult job. In fact, in many cases the propel - ler is changed after a few test runs. Proper selection is aided through the use of charts set up for various engines and boats. These charts should be studied and understood when buying a propeller. However, bear in mind, the charts are based on average boats Diagram to explain the pitch dimension through the water if there was no slippage. L_ 21" of a propeller. The pitch is the theoretical distance a propeller would <. travel U DO IT DATA©

1 - 4 SAFETY with average loads, therefore, it may be necessary to make a change in size or pitch, in order to obtain the desired results for the hull design or load condition. A wide range of pitch is available for each of the larger horsepower engines. The choice available for the smaller engines, up to about 25 hp, is restricted to one or two sizes. Remember, a low pitch takes a smaller bite of the water than the high pitch propeller. This means the low pitch propel - ler will travel less distance through the water per revolution. The low pitch will require less horsepower and will allow the engine to run faster and more efficiently. It stands to reason, and it's true, that the high pitch propeller will require more horse - power, but will give faster boat speed if the engine is allowed to turn to its rated rpm. If a higher - pitched propeller is installed on a boat, in an effort to get more speed, extra horsepower will be required. If t h e extra power is not available, the rpms will be reduced to a less efficient level and the actual boat speed will be less than if the lower - pitched propeller had been left installed. All engine manufacturers design their units to operate with full throttle at, or slightly above, the rated rpm. If you run your engine at the rated rpm, you will increase spark plug life, receive better fuel economy, and obtain the best performance CAVl TAT ION BURN from your boat and engine. Therefore, take time to make the proper propeller selection for the rated rprn of your engine at full throttle with what you consider to be an average load. Your boat will then be cor - rectly balanced between engine and propeller throughout the entire speed range. A reliable tachometer must be used to measure engine speed at full throttle to ensure the engine will achieve full horse - power and operate efficiently and safely. To test for the correct propeller, make your run in a body of smooth water with the lower unit in forward gear at full throttle. Observe the tachometer at full throttle. NEVER run the engine at a high rprn when a flush attachment is installed. If the reading is above the manufacturer's recommended operating range, you must try propellers of greater pitch, until you find the one that allows the engine to operate continually within the recommended full throttle range. If the engine is unable to deliver top performance and you feel it is properly tuned, then the propeller may not be to blame. Operating conditions have a marked effect on performance. For instance, an engine will lose rprn when run in very cold water. It will also lose rprn when run in salt water as compared with fresh water. A hot, low - barometer day will also cause your en - gine to lose power. EDGE Cavitation (air bubbles) formed at the propeller. Example of a damaged propeller. This unit should Manufacturers are constantly fighting this problem, as have been replaced long before this amount of damage explained in the text. was sustained. U DO IT DATA©

You're Reading a Preview

1988 JOHNSON EVINRUDE 20HP OUTBOARD Factory Service & Work Shop Manual

Description

Reviews

Q&A

Recently Viewed