Trimmer does not come up to speed. Changed the gas & cleaned air filter. How do I adjust carburetor.

Try this adjustment.
https://chaika.net/how-to-adjust-the-husqvarna-128-trimmer/

Carburetor adjustments are needed for idle mixture and high speed. The piston rings may be excessively worn from the abuse by the previous owner.

Hi David, bring the high speed screw out until it accepts throttle, regards Phil.

No more Mr. nice guy. But it sounds like your just out of adjustment, try readjusting your high idle screw. Good Luck..

This could be from a bad fuel filter (has a dark appearance when dry), from the spark arrestor screen in the muffler being plugged up with carbon deposits (take out the spark arrestor screen and clean it by burning off the carbon deposits), or the carburetor needs to be adjusted. If the carburetor needs to be adjusted I would take it to the nearest Stihl dealer that has a Gold Certified Technician. That way the unit is adjusted properly and is in good running condition. You can find a local dealer with the dealer locator. The link is HERE.

This is what a "General service" looks like at www.arcolawn.com

• (Mower 2 cycle GS)

GENERAL SERVICE:
1. SHARPENED & BALANCED BLADE
2. REMOVED BLOWER HOUSING & CLEANED COOLING FINS
3. REPLACED SPARK PLUG
4. FLUSHED FUEL SYSTEM
5. CLEANED CARBURETOR HOUSING
6. LUBED CABLES
7. CHECKED OIL SEALS
8. SERVICED AIR FILTER
9. CLEANED EXHAUST PORTS
10. TESTRAN & ADJUSTED.

• (Mower 4 cycle gs)

GENERAL SERVICE 1. SHARPENED & BALANCED BLADE 2. REMOVED BLOWER HOUSING & CLEANED COOLING FINS 3. REPLACED SPARK PLUG 4. CHANGED OIL 5. FLUSHED FUEL SYSTEM 6. CLEANED CARBURETOR 7. LUBED CABLES 8. CHECKED OIL SEALS 9. SERVICED AIR FILTER 10. TEST RAN & ADJUSTED.

• (rider tuneup)

Tune up
1.TIGHTENED ENGINE MOUNTING BOLTS
2. INSPECTED BOTTOMOIL SEAL.
3.TEST GOVERNOR OPERATION & ADJUSTEDRPM'S.
4.CHECK SHAFT BEARING.
5.REMOVED BLOWER HOUSING &CLEANED COOLING SYSTEM.
6. REPLACED SPARK PLUG
7.CHANGED OIL.
8.REPLACED OR CLEANED AIR FILTER.
9.ADJUST FUEL/AIR MIXTURE & SPEED LIMIT SCREWS.
10.REPLACED FUEL FILTERS AS REQUIRED.
11.CHECK FUELLINES, VALVES, & CLAMPS.
12.INSTALL FRESH FUEL IN GASTANK.
13.SHARPEN BLADE(S) & CLEAN UNDER BLADE COVER.
14.CHECK DECK, EXAMINE BELTS, PULLEYS.
15. EXAMINETRANSMISSION/DIFFERENTIAL FLUID LEVELS,
16.CHECKGREASE FITTINGS, WHEELS, WHEEL BEARINGS, HEIGHTADJUSTER.
17. CHECK CABLES & CONTROLS ADJUST BRAKE &CLUTCH.
18. CHARGE & TEST BATTERY. (IF EQUIPPED).
19. TESTSAFETY SYSTEMS.
20.REMOVED CYLINDER HEAD & CHECKEDCYLINDER FOR WEAR/DAMAGE. CHECKED ROD BEARINGPLAY. 21.CHECKED VALVES FOR PITTING, WARPING, CARBONBUILDUP & SEATING.
22.CHECKED VALVE STEM CLEARANCESFOR EXCESSIVE WEAR.
23.CLEANED CARBON BUILDUP FROMCOMBUSTION CHAMBER.
24.MACHINED HEAD FLAT.
25.CHECKEDTIMING KEY FOR DAMAGE.
26.CLEANED OR REPLACED POINTSAND CONDENSER (AS NEEDED).
27. SET TIMING. ADJUSTEDMAGNETO AIR GAP.
28.CHECKED THROTTLE SHAFT FOREXCESSIVE WEAR & REPLACED IF NEEDED.
29.DISASSEMBLED& CLEANED CARBURETOR. REPLACED DIAPHRAGM, NEEDLE &SEAT, NEEDLE VALVES ETC. AS NEEDED.(see carburetor section)



I hope this helps! get parts for the service at a dealer like www.arcolawn.com

Sounds like you will need to clean your carburetor.
Sometimes you can get by with priming it a few times, and letting it
run a few times like that and it will flush the gunk out of the jets,
but most of the time you will need to rebuild the carburetor.
If the mower is over a couple years old, then I also recommend that you
buy and install a new carburetor repair kit, because the diaphragm will
get hard and that will cause it to be hard to crank.
When you clean your carburetor and remove the jet screws, count the
number of turns it takes to seat the jets from their original position.
That way when you go to put the jets back in, you know how many turns
they were in/out.
Please do not forget to rate me, Thanks
Good Luck, I hope this helped

Morning William:
Acceleration is the "L" needle, try 1/8 turn CCW. No better 3/16 CW.
Please install a new filter on the fuel line, you will be beat to death with carburetor overhauls if you do not.
Carburetor Adjustment by Madsens.com
http://www.madsens1.com/saw%20carb%20tune.htm

• CW is leaner; to lean will destroy the saw. If over tightened closed (CW) the adjustment screw faces are easily marred; marred adjustments are difficult to impossible to set properly.
• Clean the air filter; adjusting with a dirty filter can cause a run lean condition once cleaned and the saw run.
• Clean the spark arrestor and muffler; if the saw cannot exhale it cannot inhale.
• There are 2 wav (sound - idle & full - may not be highlighted) files that I find most helpful, I think you will too.

If you have more questions or need additional help please reply below and I will get back to you. Thank you for using FixYa and Good Luck. HTH
Lou

If it is a relatively new unit it should have the carburetor adjusted after the first few hours of use. If it stalls upon accelleration the low speed adjustment on the carb needs to be opened a little bit. If it runs a few minutes and then stalls it could be the high speed jet needs to be opened or the fuel filter is clogged.

Since the air from the air filter does not go through the carb, the carb cleaner will not either. If you remove the carb and spry all of it that you can get to, you may get the plug. If you were to open the carb and go through it and clean it you would need to get new gaskets and maybe that will do the job. You may be able to adjust the carb. There is a "hi" and "low" setting. Try adjusting the "hi"...Lee