Chainsaws

Karen, I feel your pain.  I have been there.  I can explain how to resolve your issue.  I read that the saw has been to the shop, so I assume the air filter is very clean and the rest of the saw is also.  it must be kept that way to eliminate those possibilities.

factory jet settings are just slightly rich.  now, at higher altitudes the air is thinner (less oxygen), so less air is going into the cylinder and even more fuel gets in.  so now a just slightly rich mixture becomes a way too rich mixture, and it is entering the cylinder.

"Leaning out" the mix will resolve the problem, and I will explain "how to"  in detail.  this might require buying extra jets in two smaller  sizes, and 2 larger sizes for the high, and for the low, marked "H" & "L" on the saw.   but I doubt it.

firstly, buy the set of 4 carburetor adjustment tools that are offered on the amazon site.  they are very inexpensive and at first glance, the set of 4 look similar to screwdivers.  but the business ends of these drivers are very different as they have specialized tips.

now that you have the carb adjust tools, lets get started.  please make certain that the compression relief valve is closed, and remains in the closed position.  even if you must remove it from the jug and close it manually, then carefully re-install it..

while the saw is on fairly level ground, place your toes over the lower handle, and free hand on the handlebar pushing down, and with the clutch brake band disengaged, sharply start the saw without overpulling the recoil starter.  after starting up at freewheel idle, rotate the "L" adjuster until engine sound is optimized and sounding healthiest.  then as you slowly accelerate the throttle, rotate the "H" adjuster until engine sound is optimized and sounding healthiest at WOT. even an untrained mechanic will easily notice the difference.  just make incremental adjustments slowly but deliberately.  please be very careful not to allow the chain to make any contact with the dirt.

after reaching the optimum performance level, slap on the brake and confirm the engine will not be strangled to death by the clutch brake. it should continue to idle just fine.

now, if engine performance can not be optimized, then the real trial and error work must begin. as I said before, it might be necessary to buy larger and smaller jets.  I have 3 sizes above and below each standard jet.  you only need 2 over and 2 under each one.  the combinations and possibilities are simple trial and error.  it will take time and patience, but once you find the right set-up, you will always know which jets go where at high altitude.  also, you will know the standard sizes that go back in where, at sea level. or at lower elevations.  and you might just find that you needed to do it at home as well.

some woodsmen set 1 carb for high country, and another for lower elevation. and simply change carburetors when traveling up the mountain.  some woodsmen set up 1 saw for high country, and another for lower elevations.  I have several saws that I use for differing types and sizes of timber, but I just re-jet when changing elevations.  it becomes easier with time.

please try these changes staying patient and calm, but don't give up.  the right combination will be the one not tried.

good luck Karen.  please reach out if you need help for any reason.

sincerely, Robert...

Karen, I just read the reply mail.  I understand not wanting to do much on the saw while in warranty, but we all know chainsaws require much love.  as far as "autotune" carburetors are concerned,  they acclimate to barometric fluctuations in a small way, they compensate for some change with levels of humidity. but everyone that has clouds below them can testify that the "autotune" is just not up to the challenge.  I just bought a new 576xp G with a standard carburetor intentionally.  a standard carb is at the ready for your saw as well.  they are cheaper than one might think, and if you like the idea of having a saw that works in the bed of your truck, instead of one in the shop that doesn't, then you should re-consider, and take my advice.  the intake manifold should accommodate the carburetor and match identically.  the throttle linkage, choke linkage and impulse hose should match up as well.

whatever your decision, I wish you good luck, and if you need to ask advice on "how to" then I will be happy to do what I can to help out. 

I am a professional saw mechanic, but I don't represent Husqvarna.  I just try to assist all of the woodsmen that need genuine good help, when Husqvarna fails them time and again...