Jonsered 2149 Turbo Manual
Do not over tighten the H and L needles you will ruin the needle seats (clockwise closes the needle jet, counter clockwise opens the needle jet) There is no air mixture needle on a chainsaw carb (2 cycle engine) all are gas mixture needles H - high speed operation, L - low speed operation. The saw carburetor operates like a 4 barrel carb on a 350 chevy, runs on 2 but kicks in all 4 when you hammer it. Turn the H needle to 1(one) full turn open (counter clockwise). Turn the L needle to 1 1/4 (one and one quarter) turn open (counter clockwise). NEVER EVER close the H needle to less than 3/4 open or the L needle to less than 1 turn open. If you do you will burn the saw up from lack of oil lubrication. I have several Jonsereds saws a 52E, 451EV, 49SP, 520SP, 621 race saw, 630, 70E, 70E race saw, 80E and last but not least a 90E.
I worked many years for the importer and distributor of Jonsereds as a Territorial Rep. All my saws run like a top. My newest saw is a 1984.
I chainsaw carve and cut firewood with all of them year round. In short I like-em, they're the best. I find that all my saws run the best and strongest with the carb set at around 7/8 turn open on the H needle and just above 1 turn open on the L needle.
The idle screw I set last after the saw responds correctly to the carb settings. I quick throttle the saw to make sure the saw picks up RPM and doesn't fade out, put in a log to make sure it maintain tourque under load and not bogg down (tweak the H & L if needed, remembering the 7/8 - 1 1/4 rule I adjust the idle screw to where the saw sound smooth and un-labored at idle. I never let it idle to where the chain moves when it idles. For safety reasons. Hope this helps.
Jonsered 2149 Turbo
EdN Posted on Dec 27, 2015. Usually you can tune these rather easily. Turn both adjustment needles clockwise until snug. Back both out 1 full turn Now on the L needle, you adjust this while the saw is idling.
Jonsered 2149 Turbo Manual
1/4 counter clockwise increments. The H needle you adjust while pressing the throttle in and holding it in as you turn the needle as well counter clockwise. In the meantime, I will try and find if they post the actual settings which are more based on the engine capacity/ cc. The model of the particular carburetor will vary saw to saw. Oct 10, 2015.