New To Tuning - A Few Questions

[Artemis]

Hey there, I wanted to adjust the carb settings on my Husky 445. It has the high and low idle screws, as well as a screw with a T - which i am assuming is my butterfly screw or standard idle screw??

I'm prudy green with tuning as this is my first saw, but i did try tuning my dads small stihl saw a while ago. I ran it to lean and killed it, so I had to buy him a new one. Lesson has been learned, and i dont want to have that experience with my own saw. Mine is brand new and I noticed on the H and L screws that they are not slotted for a screwdriver. instead they have splines/teeth that I have never seen before. I wanted to tune the L screw to make the saw have better throttle response at the low RPM, but im not sure if i want to tamper with it yet... I heard that adjusting the H screw may require you to adjust the L screw after to compensate for small changes, but will i have to tune the H screw if I tune the L first instead? It seems to be running quite well at the top end with some minor 4 stroking before the cut, so I wont adjust the H screw.

I did want to turn up my idle a bit though, so I adjusted the T screw. I turned it in a 1/4 turn and the saw died. Turns out that I need to turn the T screw out to raise my idle. I always thought clockwise (turning in) would raise the RPM...?

Anyways Im sure the splines on the carb screws is no big deal and that adjusting them will be like any other chainsaw carb, but i thought i would double check with you guys first. What do you think?

How do you adjust your L screws? what do you listen/feel for?

Any other advice is great!

Thanks!

[CTYank]

Warm engine fully first.
Adjust the L mixture before the H, since some fuel flows from the idle "circuit" at high speed, but not conversely. Adjust idle speed so it's comfortably below clutch engagement speed. Adjust L mixture for highest speed, then a little richer a/r for good response. Repeat idle speed/mixture adjustments until satisfied. (Give L mixture adjustments a little time to have full effect, since some fuel can be stored in the crankcase.)
Sounds like the H adjustment is fine. Engine should 2-stroke cleanly in the cut, but  4-stroke lightly when you lighten the load a bit, still @WOT.
A husqy carb-adjustment tool will fit the splined screws, but they're almost impossible to find now. As a workaround, a crimp-on connector that can be shoved over the screw splines and crimped onto a single-strand copper wire will do the job.
Keep the chain SHARP and the fins clean.
If it ain't broke, don't fix it, as you saw earlier. Good Luck.  8)

[JohnG28]

You likely won't get one of those spline tools in any store. They're a control device of sorts to keep the owner from changing settings for emissions compliance. They can be found on ebay if you want,  or you should be able to take it back to the dealer you bought it from and have them do it. That's also a good idea if you want keep the warranty.  ;)

[mad murdock]

If you have a decent selection of Allen wrenches,(metric/standard), you oft times can find one that will work to adjust the spline screw heads. There are screwdriver bit sets that have the exact fit tip for those, but access is a problem with the covers on using one of those(too fat to fit through the small hole in the cover). Don't over lean a saw, aircooled engines use fuel to help cool under loads.

[SteveinUT]

Here's a set which includes the splined driver. I know they are available by themselves, but damned if I could find one in a quick search.

http://www.amazon.com/Cycle-Carburetor-Adjustment-Includes-530035560/dp/B00DQADGUM?tag=blogoffline-net-20&linkCode=w13&linkID=GTTHU5PLJDWM2C2R&ref_=assoc_res_sw_result_1

[ZR900]

Here's a set which includes the splined driver. I know they are available by themselves, but damned if I could find one in a quick search.

http://www.amazon.com/Cycle-Carburetor-Adjustment-Includes-530035560/dp/B00DQADGUM?tag=blogoffline-net-20&linkCode=w13&linkID=GTTHU5PLJDWM2C2R&ref_=assoc_res_sw_result_1

Is this it? http://www.amazon.com/Poulan-Weedeater-530035560-Adjusting-Husqvarna/dp/B00K6NEODA/ref=pd_sim_lg_5/180-6251127-6461336?ie=UTF8&refRID=1C3BBZS3H9H7QSK2DZC6

[double clutchin weasel]

The plastic tube idea is a good one.  Also, as mentioned, some interchangeable-tip screwdrivers have a spline that can work.

One of my cohorts used a plastic (or maybe copper) tube to remove his completely, then used a thin slitting disc to put a nice little screwdriver slot in them.  Looked very nice...and it actually worked!

But, like the man said, if it ain't broke...