Stihl MS 651 User Manual

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STIHL MS 651
Instruction Manual

Stihl MS 651 Specifications

General

Sound pressure level	106 dB(A)
Chain pitch	3/8"
Weight (without cutting equipment)	7.4 kg
Recommended bar length	50-60 cm
Engine Displacement	91.1 cc (5.56 cu in)

Summary

Guide to Using this Manual

Pictograms

Explains symbols used in the instruction manual for clarity and understanding.

Symbols in text

Defines text symbols used in the manual to convey important warnings and notices.

Engineering improvements

Notes that STIHL may modify products, potentially updating manual content.

Safety Precautions

General

Covers essential safety practices, local regulations, and operator fitness for use.

Intended use

Specifies the authorized uses of the machine and warns against modifications.

Clothing and Equipment

Details required personal protective equipment (PPE) for safe chainsaw operation.

Transport

Cleaning

Accessories

Refuelling

Before Starting Work

Starting the chain saw

During operation

Reactive Forces

Dangers of kickback

Details the severe risks associated with kickback, which can result in fatal cuts.

QuickStop chain brake

Describes the function of the chain brake in reducing injury risk during certain situations.

Reducing the risk of kickback

Provides techniques and precautions to minimize the likelihood of kickback.

Working Techniques

Cutting

Instructions for safe cutting practices, including throttle control and visibility.

When working at heights:

Always use a lift bucket

Specifies the use of a lift bucket as the sole safe method for working at heights.

Never work on a ladder or in a tree

Prohibits working on unstable platforms like ladders or directly in trees.

Never work on an insecure support

Warns against using any unstable or insecure platform for work.

Do not work above shoulder height

Advises against operations that require reaching significantly above shoulder level.

Never operate your power tool with one hand

Emphasizes the importance of using both hands for secure control.

When cutting small logs:

Use a sturdy and stable support – sawhorses.

Recommends using a stable sawhorse for cutting small logs.

Never hold the log with your leg or foot.

Prohibits using body parts to secure logs during cutting.

Never allow another person to hold the log or help in any other way.

Discourages external assistance in securing logs during cutting.

Lying or standing logs under tension:

Ripping cut:

Preparations for Felling

Determine direction of fall and escape path.

Crucial step to plan the tree's fall direction and safe escape routes.

Select gap in stand into which you want the tree to fall.

Guidance on choosing the landing spot for the falling tree.

Pay special attention to the following points:

Highlights key factors to consider before felling, like lean, wind, and tree soundness.

Preparing work area at base of tree

Felling Notch

Preparing felling notch

Step-by-step guide to creating the felling notch with correct angles.

Determine direction of fall with gunning sight on shroud and fan housing

Making Felling Notch

Check direction of fall

Sapwood cuts

Basic Information on Felling Cut

Stump dimensions

Information on stump dimensions related to felling cuts and hinge width.

Plunge cutting

For relieving cuts during bucking

Specific application of plunge cutting for relieving cuts.

For wood carving

Mentions plunge cutting for wood carving, a less common use.

Felling wedges

Choosing Right Felling Cut

Felling Cut with Stabilizing Strap (Normal Tree)

Describes felling cuts for normal trees, detailing stabilizing strap usage.

Felling Cut with Stabilizing Strap (Normal Tree)

A) Small diameter trees

Specific felling cut method for trees smaller than the guide bar length.

B) Large diameter trees

Specific felling cut method for trees larger than the guide bar length.

Felling Cut with Holding Strap (Leaner)

A) Small diameter trees

Specific felling cut method for leaning trees smaller than guide bar length.

Felling Cut with Holding Strap (Leaner)

B) Large diameter trees

Specific felling cut method for leaning trees larger than guide bar length.

Cutting Attachment

Chain Scabbard

Fitting Chain Scabbard Extension

Mounting the Bar and Chain

Removing the chain sprocket cover

Procedure for removing the chain sprocket cover before mounting.

Fitting the saw chain

Detailed instructions on how to fit the saw chain onto the guide bar and sprocket.

Tensioning the Chain

Checking Chain Tension

Fuel

STIHL MotoMix

Recommends STIHL's ready-to-use fuel mix for engine longevity and proper ratio.

Mixing Fuel

Guidance on the correct mix ratio for gasoline and two-stroke engine oil.

Storing Fuel

Fueling

Preparing the machine

Steps to take before fueling, such as cleaning the cap area.

Opening

Instructions for opening the fuel filler cap correctly.

Closing

Filling up with fuel

Chain Lubricant

Filling Chain Oil Tank

Preparing the machine

Steps to take before filling the chain oil tank, such as cleaning.

Filling chain oil tank

Process for filling the chain oil tank.

Oil pump setting for increased oil delivery rate

Checking Chain Lubrication

Chain Brake

Locking the chain

Describes how the chain brake locks the chain for safety.

Releasing the chain brake

Check operation of the chain brake

Chain brake maintenance

Winter Operation

Pre-heat carburettor at temperatures below +10 °C

Method to prevent carburetor icing in cold temperatures.

At temperatures below -10 °C

Mounting the cover plate (special accessory)

Starting / Stopping the Engine

Positions of Master Control Lever

Explains the different positions of the master control lever for engine operation.

Holding the Saw

On the ground

Describes how to hold the saw for starting when placed on the ground.

Between knees or thighs

Describes how to hold the saw for starting when positioned between the legs.

Cranking

Starting the Saw

Decompression valve

Explains the function and use of the decompression valve for easier starting.

When engine begins to fire

As soon as the engine runs

At very low outside temperatures

Stopping the Engine

If the engine does not start

Operating Instructions

During the break-in period

Specific instructions for the initial use of a new chainsaw.

During work

Day-to-day operating advice, including mixture adjustments and chain brake usage.

Check chain tension frequently

Emphasizes the importance of regular chain tension checks.

Chain cold

How to check chain tension when the chain is cold.

Chain at operating temperature

How to check chain tension when the chain is warm.

After a long period of full-throttle operation

Procedure for cooling the engine after extended high-speed use.

After finishing work

Steps to take after completing work, including chain slackening.

Short-term storage

Guidance for storing the machine for short periods.

Long-term storage

Refers to detailed instructions for long-term storage.

Oil Quantity Control

Standard setting

Describes the default oil flow setting and how to adjust it.

Setting for increased oil delivery rate

Taking Care of the Guide Bar

Remove Air Filter

Cleaning the Air Filter

Adjusting the Carburetor

Basic information

General information about the factory carburetor settings.

Standard setting

Details the standard carburetor settings and checks before adjustment.

Setting the idle speed

How to adjust the idle speed for proper engine operation.

Engine stops when idling

Saw chain rotates at idle speed

Speed erratic when idling; poor acceleration (despite standard setting of low speed adjusting screw)

Correcting the carburetor setting for use at high altitudes

Spark Plug

Removing the spark plug

Procedure for safely removing the spark plug.

Checking the Spark Plug

Steps to inspect the spark plug for condition and gap.

Installing the spark plug

Instructions for correctly installing a new or cleaned spark plug.

Storing the Machine

Checking and Replacing the Chain Sprocket

Fit new chain sprocket

Steps for installing a new chain sprocket onto the saw.

Maintaining and Sharpening the Saw Chain

Sawing effortlessly with a properly sharpened saw chain

Explains the benefits of a sharp saw chain for efficient cutting.

Chain pitch

Sharpening and side plate angles

A Sharpening angle

Specifies the correct sharpening angle for different chain types.

B Side plate angle

Explains the side plate angle and how it's achieved.

File holder

Proper sharpening

Check angle with file gauge

Depth gauge setting

Lowering the depth gauges

Sharpening tools (special accessories)

Minimize Wear and Avoid Damage

Maintenance Work

Emphasizes performing regular maintenance operations as described.

Antivibration elements

Air inlet on fan housing

Cylinder fins

Carburetor

Spark plug

All accessible screws and nuts (not adjusting screws)

Chain catcher

Exhaust port

Safety labels

Parts Subject to Wear and Tear

Main Parts

Specifications

Engine

Specifications related to the chainsaw's engine, including displacement and power.

Ignition System

Details about the electronic magneto ignition system and spark plug.

Fuel System

Specifications for the fuel system, including tank capacity.

Chain Lubrication

Information on the automatic oil pump and oil tank capacity.

Weight

Specifies the dry weight of the chainsaw without bar and chain.

Cutting Attachment

Specifications for cutting attachments, including guide bars and chains.

Chain Sprocket

Details about chain sprockets, including tooth count and chain speed.

Sound and vibration levels

Measured sound pressure, sound power, and vibration levels according to standards.

Chain pitch .404"

Chain pitch .404", with loop handle

REACH

Exhaust Emissions

Ordering Spare Parts

Maintenance and Repairs

Disposal

EC Declaration of Conformity