Jonsered 70C, 50C manual Maintenance, Carburettor

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MAINTENANCE

Carburettor

Your Jonsered product has been designed and manufactured to specifications that reduce harmful exhaust fumes.

Function, Basic settings, Fine adjustment

WARNING! Do not start the chain saw unless

!the bar, chain and clutch cover (chain brake) are fitted, otherwise the clutch may come loose and cause personal injury.

Function

•The carburettor governs the engine’s speed via the throttle control. Air and fuel are mixed in the carburettor. The air/fuel mixture is adjustable. Correct adjustment is essential to get the best performance from the machine.

•The setting of the carburettor means that the engine is adepted to local conditions, for example, the climate, altitude, fuel and the type of 2-stroke oil.

•The carburettor has three adjustment controls:

-L = Low speed jet

-H = High speed jet

-T = Idle adjustment screw

TH

L

•The L and H-jets are used to adjust the supply of fuel to match the rate that air is admitted, which is controlled with the throttle. If they are screwed clockwise the air/fuel ratio becomes leaner (less fuel) and if they are turned anti- clockwise the ratio becomes richer (more fuel). A lean mixture gives a higher engine speed and a rich mixture gives a lower engine speed.

•The T-screw regulates the throttle setting at idle speed. If the T-screw is turned clockwise this gives a higher idle speed; turning it anti-clockwise gives a lower idle speed.

Basic settings and running in

The basic carburettor settings are adjusted during testing at the factory.

Avoid running at a too high speed during the first 10 hours.

CAUTION! If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

Rec. idle speed: 2700 rpm

WARNING! Contact your servicing dealer, if

!the idle speed setting cannot be adjusted so that the chain stops. Do not use the chain saw until it has been properly adjusted or repaired.

Fine adjustment

When the machine has been ”run-in” the carburettor should be finely adjusted. The fine adjustment should be carried out by a qualified person. First adjust the L-jet, then the idling screw T and then the H-jet.

Conditions

•Before any adjustments are made the air filter should be clean and the cylinder cover fitted. Adjusting the carburettor while a dirty air filter is in use will result in a leaner mixture next time the filter is cleaned. This can give rise to serious engine damage.

•Do not attempt to adjust the L and H jets beyond either stop as this could cause damage.

•Now start the machine according to the starting instructions and let it warm up for 10 minutes. CAUTION!

If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

•Place the machine on a flat surface so that the bar points away from you and so that the bar and chain do not come into contact with the surface or other objects.

Low speed jet L

Turn the low speed jet L clockwise until it stops. If the engine accelerates poorly or idles unevenly, turn the low speed jet L anticlockwise until good acceleration and idling are achieved.

CAUTION! If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

Final setting of the idling speed T

Adjust the idle speed with the T-screw. If it is necessary to re- adjust, turn the T-screw clockwise while the engine is running, until the chain starts to rotate. Then turn counter-clockwise until the chain stops. A correctly adjusted idle speed setting occurs when the engine runs smoothly in every position. It should also be good margin to the rpm when the chain starts to rotate.

WARNING! Contact your servicing dealer, if

!the idle speed setting cannot be adjusted so that the chain stops. Do not use the chain saw until it has been properly adjusted or repaired.

High speed jet H

At the factory the engine is adjusted at sea level. When working at a high altitude or in different weather conditions, temperatures and atmospheric humidity, it may be necessary to make minor adjustments to the high speed jet.

CAUTION! If the high speed jet is screwed in too far, it may damage the piston/cylinder.

When test run at the factory, the high speed jet is set so that the engine satisfies the applicable legal requirements at the same time as achieving maximum performance. The carburettor’s high speed jet is then locked using a limiter cap in the fully screwed out position. The limiter cap limits the potential to adjust the high speed jet to at most half a turn.

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Contents Operator’s manual EPA KEY to Symbols Key to symbolsContents EPA Safety Instructions Machine′s safety equipmentPersonal protective equipment Chain brake and front hand guard Chain catcher Stop switchThrottle lock Right hand guardChecking the front hand guard MufflerChecking brake band wear Checking the inertia brake releaseChain catcher Stop switchThrottle lock Right hand guardCutting equipment designed to minimise kickback Cutting equipmentGeneral rules MufflerSome terms that describe the bar and chain Sharpening your chain and adjusting raker clearanceChain General information on sharpening cutting teethGeneral advice on setting raker clearance Sharpening cutting teethIf the raker clearance is too large Setting the raker clearanceTensioning the chain Cause serious or even fatal injuryLubricating cutting equipment Checking wear on cutting equipment How to avoid kickbackWhat is kickback? Chain drive sprocketDo not let go of the handles General safety precautions StartingGeneral working instructions Fuel safetyBasic safety rules Transport and storageBasic cutting technique GeneralTerms Cutting LimbingFelling direction Tree felling techniqueSafe distance Clearing the trunk and preparing your retreatFelling cut Cutting the trunk into logs General adviceFreeing a tree that has fallen badly Freeing a trapped treeWhat is WHAT? What is what on the chain saw?Assembly Fitting the bar and chainFuel Handling FuelChain oil Fuelling Cold engine Starting and StoppingStarting and stopping Warm engineStopping Maintenance CarburettorChanging a broken or worn starter cord Correctly adjusted carburettorStarter Tensioning the recoil springMuffler Air filterSpark plug Fitting the starterWhen making adjustments Adjustment of the oil pumpCentrifugal cleaning Turbo Needle bearing lubricationWinter use Heated handlesElectrical carburettor heating CanadaDaily maintenance Weekly maintenance Monthly maintenanceBelow you will find some general maintenance instructions Technical Data Technical dataCS 2171/WH 050/1,3 mm Bar ChainLength, inches Pitch, inch Max nose radius 058/1,5mmFederal Emission Control Warranty Statement Your Warranty Rights and ObligationsPage 1088917-95

50C, 70C specifications

The Jonsered 70C and 50C chainsaws represent a pinnacle of craftsmanship and engineering excellence in the world of power tools. Designed for both professional and avid DIY enthusiasts, these models offer a blend of power, performance, and user-friendly features that elevate the cutting experience.

At the heart of both the Jonsered 70C and 50C is their powerful engine output. The 70C boasts a robust 70cc engine, delivering high torque and efficiency for demanding tasks, while the 50C is equipped with a nimble 50cc engine, perfect for lighter, more agile cutting projects. This versatility makes the chainsaws suitable for a wide range of activities, from felling trees to limbing and pruning, ensuring that they cater to varying user requirements.

One notable feature of the Jonsered 70C and 50C is their advanced air filtration systems. These systems are designed to enhance the longevity of the chainsaw's engine by preventing dust and debris from entering the combustion area. This means less maintenance and more time spent operating the chainsaw, making it an ideal choice for both professional lumberjacks and casual users.

Ergonomically designed, the handle of both models offers excellent grip and comfort, reducing user fatigue during extended use. The lightweight construction of the saws enables effortless maneuverability and control, allowing users to execute precise cuts without strain. Additionally, the quick and easy chain tensioning system facilitates fast adjustments, ensuring that the chain remains in optimal condition for continuous cutting.

Safety features are paramount in the design of the Jonsered 70C and 50C. Each model incorporates a chain brake and throttle lock to enhance user safety while operating, minimizing risks associated with kickback and accidental starts. The designs also emphasize low vibration, which further protects the user's hands and arms from fatigue, promoting a safer and more enjoyable cutting experience.

With their blend of power, efficiency, and advanced technology, the Jonsered 70C and 50C chainsaws are exceptional tools for anyone seeking reliability and performance in the field. Whether for professional logging or home landscaping, these chainsaws embody the quality and innovation expected from the Jonsered brand.
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