Jonsered CS 2153 manual High speed jet H, Correctly adjusted carburetor

MAINTENANCE

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 carburetor’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.

Correctly adjusted carburetor

When the carburetor is correctly adjusted the machine accelerates without hesitation and the machine 4-cycles a little at max. speed. It is also important that the chain does not rotate at idle. If the L-jet is set too lean it may cause starting difficulties and poor acceleration. If the H-jet is set too lean the machine will have less power, poor acceleration and could suffer damage to the engine.

Checking, maintaining and servicing chain saw safety equipment

Note! All servicing and repair work on the machine requires special training. This is especially true of the machine′s safety equipment. If your machine fails any of the checks described below we recommend you to contact our servicing dealer.

Chain brake and front hand guard

Checking brake band wear

Brush off any wood dust, resin and dirt from the chain brake and clutch drum. Dirt and wear can impair operation of the brake.

Regularly check that the brake band is at least 0.024 inch (0.6 mm) thick at its thinnest point.

Checking the front hand guard

Make sure the front hand guard is not damaged and that there are no visible defects such as cracks.

Move the front hand guard forwards and back to make sure it moves freely and that it is securely anchored to the clutch cover.

Checking the inertia brake release

With the engine turned off, hold the chain saw over a stump or other firm object. Let go of the front handle so that the bar drops towards the stump as the chain saw rotates around the rear handle.

When the bar hits the stump the brake should be applied.

Checking the brake trigger

Place the chain saw on firm ground and start it. Make sure the chain does not touch the ground or any other object. See the instructions under the heading Start and stop.

30 – English