Yamaha 55DEHD User Manual

YAMAHA MOTOR CO., LTD.
Printed in Japan
Oct. 2006 – 1.1 × 1 !
(E_2)
Printed on recycled paper
75A
SERVICE MANUAL
688-28197-5J-11
85A
55D
55D, 75A, 85A
688_cover.qxd_1 07.9.26 16:21 Page 1

Yamaha 55DEHD Specifications

General

Brand	Yamaha
Model	55DEHD
Category	Outboard Motor
Language	English

Summary

General information

How to use this manual

Explains the manual's format and how to use it effectively.

Safety while working

Outlines crucial safety procedures to follow during maintenance and repair operations.

Identification

Details how to identify the outboard motor models and locate the serial number.

Special service tool

Lists and illustrates specialized tools required for servicing Yamaha outboard motors.

Propeller selection

Guides the selection of the appropriate propeller based on boat and motor performance needs.

Predelivery check

Provides a checklist for essential checks before delivering the outboard motor to ensure proper function.

Specification

General specification

Presents basic specifications for various models, including dimensions, weight, and performance data.

Maintenance specification

Details specific measurements and tolerances for engine and component maintenance.

Tightening torque

Lists specified torque values for fasteners in different parts of the motor for proper assembly.

Periodic check and adjustment

Maintenance interval chart

Provides a schedule for regular maintenance tasks based on operating hours and time intervals.

Top cowling

Instructions for checking the fit and condition of the top cowling and its related components.

Fuel system

Procedures for checking and maintaining the fuel system, including fuel joints and hoses.

Power unit

Covers checks for spark plug, thermostat, and cooling water passages in the power unit.

Control system

Details synchronization of carburetors, throttle cable adjustment, and timing checks.

Bracket

Procedures for checking PTT operation, fluid level, and tilt mechanisms.

Lower unit

Covers checks for gear oil level, gear oil change, and air leakage in the lower unit.

General

General checks including anodes, battery, and lubrication points.

Fuel system

Hose routing

Illustrates the correct routing of fuel and cooling water hoses on the engine.

Fuel line

Details the components and connections of the fuel line system.

Fuel pump

Covers the disassembly, checking, and assembly of the fuel pump.

Carburetor

Procedures for disassembling, checking, and assembling the carburetor.

Power unit

Power unit

Focuses on checking the compression pressure of the power unit.

Intake manifold

Details removal and checking procedures for the intake manifold and reed valve assembly.

Cylinder head, exhaust cover

Covers disassembly and checking of the cylinder head and exhaust cover components.

Crankcase

Details procedures for removing and disassembling the crankcase and its related parts.

Lower unit

Lower unit

Exploded view and parts list for the lower unit assembly.

Propeller shaft housing

Procedures for removing, disassembling, and checking the propeller shaft housing.

Drive shaft and lower case

Covers removal, disassembly, and assembly of the drive shaft and lower case components.

Shimming

Explains the process of shimming for proper gear and bearing alignment.

Backlash

Details how to measure and adjust gear backlash for forward and reverse gears.

Bracket unit

Tiller handle

Covers checks and assembly procedures for the tiller handle components.

Bottom cowling

Details the disassembly and assembly of the bottom cowling.

Upper case, steering arm

Procedures for disassembly, checking, and assembly of the upper case and steering arm.

Clamp bracket and swivel bracket

Covers disassembly, checking, and assembly of clamp and swivel brackets.

PTT unit

Details checking hydraulic pressure and assembly of the PTT unit.

PTT motor

Procedures for disassembling, checking, and assembling the PTT motor.

Gear pump

Covers disassembly, checking, and assembly of the gear pump.

Tilt cylinder and trim cylinder

Procedures for disassembling, checking, and assembling the tilt and trim cylinders.

PTT electrical system

Covers checks for the fuse, PTT relay, and trim sensor.

Electrical system

Checking the electrical component

Explains how to measure peak voltage of electrical components using special tools.

Electrical component

Provides a starboard view of the electrical components and their connections.

Ignition and ignition control system

Covers checks for spark plug, ignition coil, CDI unit, pulser coil, and charge coil.

Starting system

Details checks for the fuse, engine start switch, and engine stop lanyard switch.

Starter motor

Procedures for removing, checking, and installing the starter motor and its components.

Charging system

Covers checks for the lighting coil and Rectifier Regulator.

Troubleshooting

Troubleshooting the power unit

Provides a guide to diagnosing and resolving common issues with the power unit.

Troubleshooting the PTT unit

Offers solutions for problems related to the PTT unit's operation and hydraulic pressure.

Troubleshooting the lower unit

Helps diagnose and fix issues with the gear shift operation in the lower unit.