Stihl chainsaw 390 will not rev properly or idle properly. l need to know how to set the carberator
First thing, try new gas.
If that doesn't do it, you need to adjust the low and high speed circuits on the carb. A good starting point is 1.5 turns out from fully seated. On that saw I'm not positive if you will have access to the adjustment screws unless you pull off the plastic caps that may be covering them.
SOURCE: STIHL CHAINSAW MIXTURE SETTINGS
one turn high and low 66 has compesator carby willrun rich up high but will lean under load
SOURCE: Stihl MS 260 Pro wont run wide open or idle.
Hi brandon First change the sparkplug with the same heat range,Check and clean the gas filter with compressed air.Remove the carb and very carefully disassembly entirely.Check the gaskets and the diafragms.At the fuel pump side there is a fine screen(clean it).Check the needle,the spring and lever.Unlock the screws L and H(note how many turns are they).Put the corp of the carb in a special clean solution for 12 hours and then clean it with compressed air(something is clogged there).Put all back together and try to start the engine. regards savumihai71
SOURCE: Stihl chainsaw
Hi
First remove the cover,air filter and the carburator.Then remove the gas tank cap and the fuel filter from inside of gas tank,at the end of fuel line.Take off the fuel line from the hole of the gas tank(at the top),replace the fuel line,put all back together and start the engine.
best regards savumihai71
SOURCE: I have a husqvarna 340 chainsaw and it will not
Turn the screw labled T in a little. This will raise the idle setting. Heres a link to the manual. Look on page 29 of the .pdf
http://www.northerntool.com/downloads/manuals/195946.pdf
SOURCE: tunning specification for a stihl 028 chainsaw?
I'm not sure there are any "endorsed" tuning specs from Stihl as weather, temperature, fuel quality etc all contribute to engine performance.
Pictures of all types are all over the web.
As for the carb tuning procedure, maybe I can help?
Start with fresh fuel, all filters clean, and bar and chain installed. Also, fill the chain oil tank with bar/chain oil and VERIFY that the chain oiler works properly.
Initial fuel mixture settings (the H and L screws) should be 1.5 - 2 complete revolutions counter clockwise from lightly seated. Sight the carb's throttle plate and adjust idle screw counter clockwise until the plate stops moving.(Throttle closed completely.) Then go back clockwise 3 complete revolutions. This will produce an acceptable startup condition on a HEALTHY saw.
Clamp the bar in a STURDY bench vise and roll the chain with the shank of a screwdriver to verify it is clear. BE SAFE!
Choke the saw and pull the starter rope until the engine "burps".
NOTE: If no burp after 6 pulls, stop! Something is wrong.
After the burp, set choke to half and pull starter until it runs. The settings I gave should produce a slightly rich condition and a slightly high idle. (Chain will be in motion!)
Blip the throttle trigger and idle it down just enough to keep it running during the tune procedure.
Step 1) Using the "L" screw (closest to the engine), turn it clockwise until the engine smooths out or possibly increases RPM. Back it out slightly until the engine has a slight "LOPE" sound to it. (Like a drag car on nitro).
Step 2) Accelerate the engine to full throttle and go to the "H" screw (closest to the air filter) and slowly turn it clockwise and note the RPM increase. There will come a point when the saw will "Top-Out" and loose power. Not even enough power to turn an maintain empty chain's RPM! Go back counter clockwise to the edge of that point, and counter clockwise another fourth (1/4) revolution.
Step 3) Idle the saw back down. Again go to the "L" screw and repeat Step 1.
Step 4) Repeat Step 2.
Step 5) Idle the saw down until the chain stops moving completely. NOTE: Don't settle for a "crawling chain" condition. If the steps above are performed well and all else is healthy, you should be able to idle the engine down to a ridiculously low RPM and it will not shut off.
Hope this helps,
Dolf-
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