# Husqvarna carb tuning



## minnnt (Dec 28, 2010)

What tools do i need and what is the best way to do it?


----------



## Cliff R (Dec 28, 2010)

Most take a slotted drive long thin screwdriver. Some of the newer offerings require a special screwdriver that looks like a nut driver with a lot of splines.

I remove the limiter caps from them, and if they require the nut driver deal, I push a small peice of copper pipe over the screws and remove them. Then I slot them for a flat tip screwdriver with a very fine cutting wheel on the Dremel tool. It is best to reference their initial setting(s), and remove and replace them one at a time so you don't mix them up.

There is PLENTY of info on this site describing carb tuning. The basics are pretty easy. 

-Make sure the saw is fully up to operating temperature.

-Set the "L" screw first, and trim the idle speed screw to just below where the clutch is engaged, but not so slow the saw wants to die out after a cut is made.

-Set the "L" speed screw for the highest possible and smoothest idle, then go just a tad counterclockwise (rich) until you just hear a very slight change in engine speed/pitch. This is the base setting, and provides some additional fuel to help throttle response off idle.

-Set the "H" speed screw for best power in the cut at the richest setting(s). This is done by making sure you start out plenty rich, to a point where the engine is loosing power slightly and 4-stroking or missing heavily at no load. Make cuts and continue to lean it up for best power and speed in the cut, without the engine going lean when the load is removed.

The "H" speed screw is difficult to set on some modern saws as they have rev-limiting modules built into the coils, that fool the tuner into thinking that you have plenty of fuel coming in. You simply have to sneak up on the settings for these saws, as they are always going to 4-stroke or start missing when the load is removed from them.

I set all my saws for best power in the cut, and make sure that they 4 stroke slightly when the load is removed from them. 

It's not all about trying to make the saw rpm when setting the carburetors. There are a LOT of different engine designs out there. Some saws like less no load rpm's and respond with improved mid-range power in the cut.

All of my XP models LOVE being up near 14,000rpm's at no load, then "clean-up" the instant they see a load and make great power in the cut. The closed port 55's are the same deal. My open port 55 is more of a mid-range saw, and doesn't rpm nearly as well as the closed port models, and enjoys a richer setting from the "H" speed screw (for example).

The basic rule of thumb here for setting carburetors is to make sure that you are more in the rich direction than lean. EGT's rise sharply with lean settings, and you reduce lubrication to the engine at the same time. The sharp increase in piston speed can start to smear some aluminum over the ring(s) quickly when this happens.

Also plan on doing some very fine tuning in varying weather conditions, and with any altitude change, so keep your screwdriver with you in the woods. You may also have to fine tune for different types/grades of fuel, and oil/fuel ratios.

I have always used 40 to 1 here in premium pump gas, either Husqvarna or Stihl premium mix, and set my saws up just a tad rich vs being anywhere near lean. I absolutely want to hear them "4-stroke" at no load, or anytime the load is removed in the cut. Never had a single P/C or any other engine related problem in over 30 years of using them, and they get used a LOT!.......Cliff

PS: Here's a pic of my oldest saw, purchased new in 1980, and it still runs flawlessly everyplace, despite having about a zillion hours on it!


----------



## minnnt (Dec 28, 2010)

So will the 262 just be a simple flat screwdriver? I don't think it seems to be badly set up, I can rev it out full then sit it down and it wont stall and the chain doesn't run etc, but its always good to know. What are these other tools you talk about and what are 'caps'


----------



## Cliff R (Dec 28, 2010)

Limiter caps are widely used to limit the range of tuning provided by the mixture screws. This was done to keep the saw withing the EPA limits for emissions for the model year produced.

They meant well, but most will not run up to full potential unless the limiter caps are removed and custom tuned. Some barely run at all as delivered as they are set to lean from the factory. Echo saws are the worst I've seen for this.

Once the limiter caps are removed (I usually pull them with a fine tip drywall screws and pair of pliers), the tuner can custom set the "L" and "H" screws as described above.

The 262 should have slotted screws and require a flat blade screwdriver. The "goofy" mulitiple splined screws have shown up on some models in recent years. There are other types out there, and unless you plan on buying or making a special tool to turn them, plan on removing them and slotting them for a flat tip screwdriver.....Cliff


----------



## minnnt (Dec 28, 2010)

Thanks for that Cliff. Are the newer ones like star bolts then? Can't picture them. 

How do i get to the caps on the carb? Sorry for being a newbie! lol.


----------



## Cliff R (Dec 28, 2010)

Sort of, with a lot of really fine splines. I don't put the limiter caps back in place, but save them if the saw is under warrentee, and may need to go back to the dealer.

Actually, I've never once had a Husqvarna saw that required any Warrantee work. Any minor glitches I've corrected myself, and setting the carb up and using a good oil-fuel mix pretty much eliminates any potential for P/C failures.....Cliff


----------



## komatsuvarna (Dec 28, 2010)

:agree2::agree2: Also, brad has a video somewhere about tuning. Ill see if I can find it.


----------



## minnnt (Dec 28, 2010)

komatsuvarna said:


> :agree2::agree2: Also, brad has a video somewhere about tuning. Ill see if I can find it.



Thanks guys...


----------



## komatsuvarna (Dec 28, 2010)

Not the one I was thinking about, but its pretty good as well.

<object style="height: 390px; width: 640px"><param name="movie" value="http://www.youtube.com/v/7jYUotkZorg?version=3"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always"><embed src="http://www.youtube.com/v/7jYUotkZorg?version=3" type="application/x-shockwave-flash" allowfullscreen="true" allowScriptAccess="always" width="640" height="390"></object>


----------

