Yanmar 3TNV70 - Service Manual

Other manuals for Yanmar 3TNV70

Operation Manual142 pages

Questions and Answers

A
Alison RayAug 18, 2025
What to do if there are problems with the lubricating system in my Yanmar Engine?
- E
  Eric RodriguezAug 18, 2025
  For issues within the Yanmar Engine's lubricating system, possible causes and solutions include: * Improper lube oil properties: Use the correct lube oil. * Leakage from the lube oil piping system: Repair any leaks. * Insufficient delivery capacity of the trochoid pump: Check and repair the pump. * Clogged lube oil filter: Clean or replace the filter. * Defective pressure regulating valve: Clean, adjust, or replace the valve. * Insufficient lube oil level: Add the proper lube oil to the correct level.
J
Joseph JacksonAug 27, 2025
How to troubleshoot cooling water system issues in a Yanmar 3TNV70?
- R
  Randy MartinAug 27, 2025
  When dealing with issues in the Yanmar Engine's cooling water system, consider these points: * Excessive cooling effect of the radiator: This could be due to a defective thermostat (kept closed). * Insufficient cooling effect of the radiator: This may be caused by a defective thermostat (kept opened) or a slipping fan belt. * Insufficient cooling water level: Check for water leakage from the cooling water system. * Cracked water jacket: Repair or replace the cracked water jacket. * Slackened fan belt: Adjust the belt tension. * Defective thermostat: Check or replace the thermostat.
R
Ronald WalkerNov 7, 2025
Why is my Yanmar 3TNV70 Engine output insufficient?
- W
  Wayne DavisNov 7, 2025
  To address insufficient Yanmar Engine output, consider the following potential causes and solutions: * Improper clearance of intake/exhaust valve: Adjust the valve clearance. * Compression leakage from valve seat: Lap the valve seat. * Seizure of intake/exhaust valve: Correct or replace the valve. * Blowout from cylinder head gasket: Replace the gasket. * Seized or broken piston ring: Replace the piston ring. * Worn piston ring, piston, or cylinder: Perform honing and use oversize parts. * Seized crankpin metal or bearing: Repair or replace. * Improper arrangement of piston ring joints: Correct the ring joint positions. * Reverse assembly of piston rings: Reassemble correctly. * Worn crankpin and journal bearing: Measure and replace. * Loosened connecting rod bolt: T...

Summary

INTRODUCTION

YANMAR WARRANTIES

Yanmar Limited Warranty

Details Yanmar's standard warranty terms and coverage for engines.

Emission System Warranty

Specific warranty information for emission control systems in the USA.

SAFETY

Safety Statements

Explanation of safety alert symbols and general safety advice.

Safety Precautions

Detailed safety precautions to prevent hazards during operation and maintenance.

GENERAL SERVICE INFORMATION

Component Identification

Diagram and list identifying major engine components.

Location of Labels

Shows the location of regulatory and safety labels on the engine.

Function of Major Engine Components

Describes the function of key engine components like air cleaner and fuel filter.

Function of Cooling System Components

Explains the role of components within the engine's cooling system.

Diesel Fuel

Specifications and requirements for diesel fuel, including biodiesel.

Engine Oil

Information on engine oil specifications, viscosity, and checking levels.

Engine Coolant

Details on engine coolant specifications, handling, and capacity.

Specifications

Provides engine speed and general specification data for different models.

PERIODIC MAINTENANCE

Precautions

General precautions and important considerations for performing maintenance.

Periodic Maintenance Schedule

Summary of maintenance items and intervals for keeping the engine in good condition.

Periodic Maintenance Procedures

Step-by-step instructions for performing scheduled maintenance tasks.

ENGINE

Before You Begin Servicing

Safety and procedural notes before starting engine service.

Cylinder Head Specifications

Detailed specifications and adjustment data for the cylinder head.

Camshaft and Timing Gear Train Specifications

Specifications for camshaft and timing gear train components.

Crankshaft and Pistons Specifications

Specifications for crankshaft, connecting rods, and pistons.

Piston Ring

Specifications for piston ring dimensions, clearances, and end gaps.

Cylinder Block Specifications

Specifications related to the cylinder block, including bore and roundness.

Special Torque Chart

Specific torque values for various engine bolts and nuts.

Special Service Tools

List of specialized tools required for engine service procedures.

Measuring Instruments

Tools and instruments used for taking precise measurements during engine service.

FUEL SYSTEM

Before You Begin Servicing

Safety and procedural notes before starting fuel system service.

Introduction

Overview of the fuel system and its components.

Fuel System Specifications

Torque and test specifications for fuel system components.

Fuel System Diagram

Schematic illustrating the flow of fuel through the system.

Fuel System Components

Identifies and illustrates various fuel system parts.

Fuel Injection Lines

Procedures for removing and installing high-pressure and return fuel lines.

Fuel Injectors

Procedures for removing, testing, and installing fuel injectors.

Fuel Injection Pump

Procedures for removing and installing the fuel injection pump.

Checking and Adjusting Fuel Injection Timing

Steps to check and adjust the engine's fuel injection timing.

COOLING SYSTEM

Before You Begin Servicing

Safety and procedural notes before starting cooling system service.

Introduction

Overview of the engine's cooling system.

Cooling System Diagram

Schematic of the engine's cooling system components and flow.

Engine Coolant Pump Components

Identifies and illustrates the parts of the engine coolant pump.

Engine Coolant System Check

Procedure to check the engine coolant system for leaks.

Engine Coolant Pump

Procedures for disassembling, cleaning, inspecting, and reassembling the coolant pump.

LUBRICATION SYSTEM

Before You Begin Servicing

Safety and procedural notes before starting lubrication system service.

Introduction

Overview of the lubrication system and its components.

Oil Pump Service Information

Specifications for engine oil pressure and pump clearances.

Lubrication System Diagram

Diagram illustrating the flow of lubricating oil through the engine.

Checking Engine Oil Pressure

Procedure to check and diagnose engine oil pressure issues.

Trochoid Oil Pump

Components, disassembly, inspection, and reassembly of the trochoid oil pump.

STARTER MOTOR

Before You Begin Servicing

Safety and procedural notes before starting starter motor service.

STARTER MOTOR INFORMATION

Technical specifications and performance data for starter motors.

Starter Motor Specifications

Detailed technical specifications for starter motor components.

Starter Motor Troubleshooting

Diagnostic flowchart for troubleshooting starter motor issues.

Starter Motor Components

Identifies and illustrates the parts of the starter motor assembly.

Starter Motor

Procedures for removing, disassembling, and reassembling the starter motor.

Check Pinion Projection Length

Procedure to measure and adjust the pinion projection length.

No-Load Test

Procedure for testing starter motor performance without load.

Installation of Starter Motor

Steps for reinstalling the starter motor onto the engine.

ALTERNATOR

Before You Begin Servicing

Safety and procedural notes before starting alternator service.

STANDARD AND OPTIONAL DYNAMO INFORMATION

Information on standard and optional dynamo units.

STANDARD AND OPTIONAL ALTERNATOR INFORMATION

Information on standard and optional alternator units.

ALTERNATOR SPECIFICATIONS

Technical specifications for the Yanmar alternator.

Dynamo Specifications

Technical specifications for the Yanmar dynamo.

ALTERNATOR TROUBLESHOOTING

Diagnostic flowchart for troubleshooting alternator issues.

ALTERNATOR COMPONENTS

Identifies and illustrates the parts of the alternator assembly.

ALTERNATOR WIRING DIAGRAM

Schematic of the alternator's electrical connections.

Alternator Standard Output

Graph showing standard output current vs. alternator RPM.

Alternator

Procedures for removing, disassembling, and reassembling the alternator.

Dynamo Component Location

Identifies the location of dynamo components.

Dynamo Wiring Diagram

Schematic of the dynamo's electrical connections.

Dynamo Standard Output

Graph showing standard output current vs. dynamo speed.

Testing of Dynamo

Procedures for testing dynamo coils, output, and regulated output.

Installation of Dynamo

Steps for reinstalling the dynamo onto the engine.

ELECTRIC WIRING

Electric Wiring Precautions

Important precautions for handling electrical wiring and preventing damage.

Electric Wire Resistance

Table showing resistance values for different wire gauges.

Battery Cable Resistance

Table showing maximum allowable battery cable length based on resistance.

Electrical Wire Sizes - Voltage Drop

Chart for selecting wire sizes based on current, length, and voltage drop.

Conversion of AWG to European Standards

Table for converting American Wire Gauge (AWG) to European standards.

TROUBLESHOOTING

Special Service Tools

List of special tools for troubleshooting, like compression gauges.

Troubleshooting By Measuring Compression Pressure

Procedure for diagnosing engine issues by measuring compression pressure.

Compression Pressure Measurement Method

Detailed steps for performing a compression pressure test.

Quick Reference Table For Troubleshooting

Table correlating measured values to potential problems and corrective actions.

Troubleshooting Charts

Comprehensive charts linking symptoms, causes, corrective actions, and reference pages.

Yanmar 3TNV70 Specifications

General

Engine Model	3TNV70
Number of Cylinders	3
Bore x Stroke	70 mm x 74 mm
Combustion System	Direct injection
Aspiration	Natural
Cooling System	Water-cooled
Fuel	Diesel
Type	Vertical, water-cooled, 4-cycle diesel
Displacement	0.854 L
Fuel System	Mechanical control
Starting System	Electric starter
Lubrication System	Forced lubrication