026 carb adjustment

[pesaventoc]

I have a 20yr. old stihl 026 with three jets. Could someone talk me through the adjustment order and process. Thanks.

[GlenM]

here's a page that has a procedure:

http://www.madsens1.com/saw%20carb%20tune.htm

[pesaventoc]

Thanks Glenm, That's just  what I was looking for. I have a small cabin in Cedar Mountain,N.C. The ground has been mostly covered with snow since before Christmas. My neighbor called me here in Folly Beach, S.C. and told me I have five trees across my driveway. So, it looks like I,ll be cutting my way in on Thursday. The last time I used my saw I put it up with alcohol gas in it so had to clean the needle valves. ..Thanks for the information. I had gone to the search site but kept getting an error message.

[Ed]

You might want to check the fuel & impulse lines for rot. It might be worth the time to put in a diaghpram kit too.
My 026 is about the same age.....carb kit last year, fuel lines this week.

Ed

[GlenM]

You might want to check the fuel & impulse lines for rot. It might be worth the time to put in a diaghpram kit too.
My 026 is about the same age.....carb kit last year, fuel lines this week.

Ed

Superb idea, I've repaired saws where the fuel lines looked good, were supple, etc. but saw wouldn't run worth a flip, put in new fuel lines and then ran great.
g

[windthrown]

My old 026s are great running saws.

[pesaventoc]

I  spent the afternoon adjusting the jets. Right now at sealevel it's purriing or burping(chainsaw slang). Add3000ft and we"ll see. ??? But after 20 years I  think servicing carb and supply lines is next. :-\

[windthrown]

Going up in elevation is usually not an issue; it will run richer. Its dropping in elevation that can cause lean problems if you tune the saw at elevation and them drop (more air = leaner).

[Ed]

My old 026s are great running saws.

Mine was until last week.  :(
After checking it out, the impulse hose had swelled up where it fits the barb on the carburator, don't run worth a DanG if its sucking air.

Ed

[windthrown]

New impulse line and it will run good as new. That drives the fuel pump in the carb, BTW.

[windthrown]

BTW, to answer the OP, here is the carb tuning process from my Stihl service manual on the 026:

Make sure that the air filter is clean and the muffler screen is clear. Start by setting the H & L carb screws to the default factory nominal setting. On the 026/260 that means turn the screws in and seat them *gentley* until the screw stops, and then back them off. Back the H &L screw both out one full turn. Start the saw and run it to warm it up with the bar and chain on it. With a tach, set the idle to 3300 RPM. Then turn the L screw in or out to get the highest idle speed. Reset the L/A to 3300 RPM again, and redo the process until you get the highest idle from the L screw. Usually it is a only hair one way or the other. With the L screw set, turn the L/A (idle) screw down until the chain stops running (with the brake off) and then another quarter turn past that point.

Then set the H screw. At WOT, the saw should be set to run at about 14,000 RPM. It should burple or 4-stroke some at WOT. If it sounds clean, it is running lean. Do some cutting, and the WOT saw sound should clean up in the cut. If the saw bogs or does not cut well, adjust the H screw in or out a tad (1/16th turn) and do another cut to see if it cuts better. Redo the process until you get the best cutting saw with a burple sound running unloaded WOT. To see if the saw is running rich enough, do a good long cut at WOT. Then shut off the saw from WOT. Let it cool down and pull the plug. It should be chocolate brown. Light grey or white and it is too lean.

If you do not have an adjustable H screw, all you can do is adjust the L screw. Run a tach to check the WOT speed, and it should be about 14,000. You can also look for a replacement dual adjustable jet carb on Ebay. There are several carbs that came on the 026/260 series saws. The Walbro 194 is the best one.   

[Ed]

New impulse line and it will run good as new. That drives the fuel pump in the carb, BTW.

Ya, your correct. If I've got to tear the whole DanG saw apart for one line I'll replace both while I'm in there.  :D

Ed<----gets parts tomorrow!

[windthrown]

Yep, impulse lines can be a big PITA to replace on Stihl saws. The 026 is easier for this than the 025.

[joe_indi]

The 026 that I have drove me nuts for a couple of months.
It would run lean at times.If the carb screws were adjusted to compensate for this, it would run rich suddenly and the engine would flood.
After changing the impulse hose, the cylinder gasket, all the removable bits in the carb, the fuel hose and the pickup body, I was stumped for the cause of the problem.

The only thing to replace was the carburetor.
But before I that I went over that saw once more.
This time I was able to  find the cause of the problem. For such a well built saw I would consider what I found as its Achilles heel.
Carburetors on Stihl Pro saws that I know of have a metal nipple for connecting the fuel hose. However the 026 has a plastic one, molded onto a milled bit of metal.
This arrangement is not a sure fit one.The plastic portion moves on the milling.
On my saw air was seeping in through the joint of plastic and metal.
The only reason I was able to locate this leak was a sheer accident.
I pressurized the fuel tank (with fuel) through the air vent, to check if the air vent was working.
At about 5 psi I noticed fuel leaking out of the carb area.
I fixed the leaking connector with epoxy glue.
Its two years since that glue was put on, that 026 is still going strong.

Many was the time that I heard from acquaintances and colleagues, that the 026 is prone to carburetor related problems.In most cases that I know of, the symptoms were similar to what my saw had. I would like to think that the cause was common, that weak plastic nipple.

Joe

[Ashbored]

Thanks to Windthrown for the carb adjustment info. My 20 year old 026 had always been cantankerous and unpredictable. Recently I replaced the carb, fuel line, crankcase line, air and fuel filters and it ran well for a brief period and then started acting up - would not stay in tune. I was looking at buying a replacement saw when I ran across Windthrown's info on carb adjustment and decided to look at everything once more. I noted that the new fuel line was crimping some at the bend before the carb where the line was thinner. When the saw heated up, this softer section weakened and crimped off the fuel even more.  This is why it acted up after it was used for a while. I replaced the line that I had purchased on line with one from my Stihl dealer, adjusted the carb per instructions, and it now runs and starts better than ever.