STIHL hedgetrimmer HS82 T and R : carburator "H" screw setting???

[StarTech]

Personally even after 15 yrs I still can't tell when RPMs change by 50 rpm on the Echo line besides I do wear ear plugs most times to save my hearing.

 

[Fish]

If you have 2 units with the same carb, and 1 doesn't run right, swap the carbs and see which one runs right.

 

[StarTech]

IF doing try this be aware the air filter cover setup maybe different as two different setups was used on these hedgers depending on which choke lever was used.

 

[Flatsix]

It takes years to be able to tune handheld 2-stroke equipment efficiently and effectively by ear and using a tachometer. Not something you can read and just turn a screw. Some are easier than others.

Startech : many thanks for the papers you sent - with that I can do the adjustment of the L-screw and I know the basic for the "H"-screw. It is a pity that there is not much said or written about the "H"screw that for me is the most important adjustion that is to make on my machines. Then only write : turn H-screw 2.1/2 turns out and that is it...

I know that it is not easy to adjust the H-screw for an unexperienced fellow like me, but I am sure that when I get a good description of what to hear and see on the tach I will be able to have the good result. I have a very big garden and work a lot with 2-stroke machines, so I am aware of the difficulties in hearing, but am not new to it.

The 2.1/2 turns out for the H seems too rich for my machines. So need a procedure to be able to set it better with my ears + tachometer. It is a pity that the machine has an rpm-limiter that kicks in at 9300 rpm, otherwhise it would be much mure easier : I just turn the H till machine reaches max. 9300 rpm and that was it, but now with the rev.limiter it is not evident.

Do you think there is a way to help me with that adjusting of my "H"-screw, or do I leave it at 2.1/8 turns out like it is now??

 

[Flatsix]

IF doing try this be aware the air filter cover setup maybe different as two different setups was used on these hedgers depending on which choke lever was used.

My 2 machines "R" and "T" are both identical - they both run great but the "R" runs richer then the "T", although both have the same "turning out of the H-screw", namely both 2.1/8" out. They should do the same, both they don't.

That is why I wanted to tune each machine individually with a procedure as I have a tachometer, so I can read the rpm - if I can get a plan how to do then it will be possible to finetune each of them for optimum mixture air/fuel.
Now I think the R runs too rich although it has the same setting as the T (2.1/8 turns out).

 

[StarTech]

There is a note in the service manual about the Brazilian 82R being set at 2 turns. They run these rich is to keep them cooler as they can overheat if too lean. Especially they are tuned for high altitude and then used at sea level.

These service manual setting are probably for sea level to 2500 ft.

Also if you are at higher altitude a leaner mixture would be needed.

I usually tune to basic settings for most Stihl with limiters and finally touch up the H to where the limiter just start kicking in. This way it is still on the rich side but not excessively rich. This is because L setting does affect the H setting but H does not affect L setting.

 

[Flatsix]

There is a note in the service manual about the Brazilian 82R being set at 2 turns. They run these rich is to keep them cooler as they can overheat if too lean. Especially they are tuned for high altitude and then used at sea level.

These service manual setting are probably for sea level to 2500 ft.

Also if you are at higher altitude a leaner mixture would be needed.

I usually tune to basic settings for most Stihl with limiters and finally touch up the H to where the limiter just start kicking in. This way it is still on the rich side but not excessively rich. This is because L setting does affect the H setting but H does not affect L setting.

I do not understand this StarTech. Normally they set the H at 2.1/2 turns out. The Brazilian 82R is set at 2 turns out to run them rich. But 2 turns out is leaner then 2 1/2 turns out, isn't it? I thougt that screwing in (clockwise) makes the mixture leaner - mine sits now at 2.1/8 turn in instead of 2.5 turns in - so mine is now set leaner than the standard? Please conform because now i am getting a little confused.

 

[StarTech]

Yes turning the screws CW does lean out the mixture. Just the nature RH threaded screws.

As for why the Brazilian units are tuned differently I don't know unless they changed the mixture screws somehow or it is some government reg.

 

[Flatsix]

Yes turning the screws CW does lean out the mixture. Just the nature RH threaded screws.

As for why the Brazilian units are tuned differently I don't know unless they changed the mixture screws somehow or it is some government reg.

Startech, are you shure? So 2.1/2 turns out is leaner then 2.1/8 turns out? I thought that screwing tem IN (counterwhise) would make the mixture with less fuel - so leaner.
then instead of putting them on 2.1/8 I better put the screw on 2.5/8 as that would be leaner then the original 2.5 turns that they set as standard?

 

[Flatsix]

I will definitely continue doing it my way - screwing IN (clockwise) = leaner and screwing OUT (counterclockwise) = richer mixture. Thanks for your help with the papers you have sent .