carb adjustments on a stihl 029 and 290

[grinder1]

Hello everyone,
i purchased a couple of used stihls locally. Put new bars and chains on both. I retuned the carbs on one of them. I need to know...when turning the low and/or high carb screws out (ccw) am I richening or leaning the mixture? I retuned the 1st saw ending with holding the throttle open and setting the screw to a position that ran the saw as fast as it would run. I found out after doing this that it may be too lean....so, if i turn the screw cw is that richening or leaning? Ive been under the understanding that opening the screw (ccw) allows more air. Is this considered leaning the carb? Any help with this would be very appreciated!
Thanks in advance!
Robb

 

[cattoon]

I'll try to help

1st. the screws to adjust the carburator have nothing to do with air. There should be a reference setting of x amount of turns CCW on both screws to begin tuning. When you turn CCW you are allowing more fuel to enter the carburator and creating a richer mixture. When you go CW you are decreasing the amount of fuel allowed through the carb, leaning the mixture. I do not know the initial setting for your carb, but would probably try 1 - 1 1/2 turns CCW from a lightly seated position for both H and L screw.. Hopefully someone will be able to help more. I do know that too lean is too bad when the rings let go and the piston smears on the cylinder, from personal experience.

 

[H 2 H]

All saws will be different even the same model of saw

Tune each saw to what the saw wants not what another saw wants to run great

 

[grinder1]

so I went out and warmed the saw and pegged the throttle, turned the high screw to where the saw was running fastest then opened the screw (ccw) about another 1/8 turn to make it a little richer so as not to scorch the piston/rings/cylinder from being to lean, correct way of thinking?

 

[IEL]

The last 290 I worked on listed 1/4 turn low, 3/4 turn high... ya right, bogged when you pulled the throttle. Did my standard 1 turn each, to start, I think the low needed 1 1/8, and I tuned the high in the cut. Read up on tuning in the cut, that is the best way.

With stock settings the 290 was a gutless POS, with a proper tuning, it was still weak compared to my 034 but didnt cut too bad.

 

[sefh3]

If you saw is stock. There are limiter caps on the carb needles. These are set by the factory. Usually red in color. The best way to tune a saw is by ear. The saw needs to four stroke, clean in the cut, and stroke out of the cut. Making it the engine run to it's fastest potiental will smoke it. I would remove the limiter caps from the carb. Set them both 1 turn out. Tune from there.

Search this site and there are some great threads and video's members have posted here to help tuning.