I have two Jonsered chainsaws and a Jonsered brushcutter. There are three adjustment screws on the carburetors of these saws. Access to the adjustment screws are through three holes in the body of the saw. The holes are labelled: L, H and T.
L = Low speed jet
H = High speed jet
T = Idle adjustment screw
The L and H jets are used to adust 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 mixture becomes leaner and if the are turned counter-clockwise the mixture become richer. A lean mixture gives a higher engine speed and a rich mixture 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 counter-clockwise gives a lower idle speed.
When adjusting, first adjust the L-jet, then the T-idle screw and then the H-jet.
A forum community dedicated to living sustainably and self sufficiently. Come join the discussion about livestock, farming, gardening, DIY projects, hobbies, recipes, styles, reviews, accessories, classifieds, and more!