MTD 61 series User Manual

Professional Shop Manual
61, 65 and 70 Series Vertical Shaft Engines
MTD Products Inc. - Product Training and Education Department
NOTE: These materials are for use by trained technicians who are experienced in the service and repair of outdoor power
equipment of the kind described in this publication, and are not intended for use by untrained or inexperienced individuals.
These materials are intended to provide supplemental information to assist the trained technician. Untrained or inexperi-
enced individuals should seek the assistance of an experienced and trained professional. Read, understand, and follow all
instructions and use common sense when working on power equipment. This includes the contents of the product’s Oper-
ators Manual, supplied with the equipment. No liability can be accepted for any inaccuracies or omission in this publication,
although care has been taken to make it as complete and accurate as possible at the time of publication. However, due to
the variety of outdoor power equipment and continuing product changes that occur over time, updates will be made to these
instructions from time to time. Therefore, it may be necessary to obtain the latest materials before servicing or repairing a
product. The company reserves the right to make changes at any time to this publication without prior notice and without
incurring an obligation to make such changes to previously published versions. Instructions, photographs and illustrations
used in this publication are for reference use only and may not depict actual model and component parts.
© Copyright 2013 MTD Products Inc. All Rights Reserved

MTD 61 series Specifications

General

Brand	MTD
Model	61 series
Category	Engine
Language	English

Summary

CHAPTER 1: INTRODUCTION

Safety

Safety and operational instructions for equipment.

Maintenance

Recommended maintenance intervals for engine components.

Spark plugs

Spark plug types, gapping, cleaning, and inspection guidance.

Oil type and capacity

Recommended oil viscosity, API rating, capacity, and usage.

Changing the oil

Three methods for changing engine oil: siphon, drain plug, tipping.

Fuel system

Servicing the fuel system

Fuel filter

Valve lash

General torque specifications

CHAPTER 2: BASIC TROUBLESHOOTING

Steps to troubleshooting

General steps and approach to troubleshooting MTD engines.

Define the problem

Identifying and categorizing engine operating problems.

Identify factors that could cause the problem

Diagnosing potential causes for engine issues.

Repairing the problem

Steps involved in diagnosing and performing repairs.

Prime test

Leak-down test

Compression test

CHAPTER 3: AIR INTAKE SYSTEM

Air filter

Details on paper and foam air filters, their housings, and access.

CHAPTER 4: THE FUEL SYSTEM AND GOVERNOR

Fuel Lines

Inspect the fuel lines

The fuel filter

Troubleshooting the EVAP system

Carburetors

Troubleshooting, inspection, and cleaning of carburetors.

Disassembly and rebuilding the carburetor

Step-by-step guide for disassembling and rebuilding carburetors.

Governor

Explanation of engine speed control by the governor system.

Governor arm

Governor shaft

Governor cup and the governor gear

CHAPTER 6: STARTER AND CHARGING SYSTEMS

Recoil Starter Removal

Starter Rope

Electric starter relay

Testing the starter relay

Electric starter

CHAPTER 7: IGNITION SYSTEM

Troubleshooting the ignition system

Steps to diagnose ignition system problems.

Troubleshooting the stop switch

Testing the stop switch for proper grounding.

Spark plug removal

Ignition module

Module removal

Installing the module and setting the air gap

Steps for installing a new ignition module and setting the air gap.

Engine brake and stop switch (if equipped)

Adjusting the brake assembly (if equipped)

Flywheel

CHAPTER 9: CYLINDER HEAD

Cylinder Head

Procedures for removing the cylinder head.

Valves

Procedures for servicing valves and valve components.

CHAPTER 10: CRANKSHAFT, PISTON AND CONNECTING ROD

Engine Disassembly

Steps for disassembling the engine.

Crank shaft inspection

Procedures for inspecting the crankshaft for wear and damage.

Piston Inspection

Procedures for inspecting the piston and piston rings.

Connecting rod inspection

Procedures for inspecting the connecting rod.

Cylinder inspection

Procedures for inspecting the cylinder bore and cross hatch.

Bearings

Reassembly

Step-by-step guide for engine reassembly.

Engine specifications chart

Engine torque values chart

CHAPTER 11: FAILURE ANALYSIS

Abrasive Ingestion

Causes and symptoms of abrasive particles entering the engine.

Insufficient lubrication

Causes and indicators of insufficient engine lubrication.

Over heating

Causes and signs of engine overheating.

Over speed

Causes and consequences of engine overspeed.

Mechanical Breakage/ Wear

Reasons for mechanical failure, wear, and manufacturing defects.

Detonation/pre-ignition

Conditions leading to detonation and pre-ignition.