Stihl Pro 026 Manual
Rick8809 You said that yours just shuts-off after it gets warm. That could be interpreted different ways.
If it happens at WOT or partial throttle then my 026 experience was different. If it just shuts-off if allowed to drop to idle when hot then read on. Here are more details on my experience with my 026 many years back. (15+) My 026 started fine, idled fine, ran great when cold until it got hot.
Stihl also manufactures a saw for almost every imaginable use. The 026 Pro and the 028 AV Super are very similar in design and build. Stihl 026 Pro Vs.
Once hot it ran great as long as I did not let an idle stabilize. It would die (shut-off) if it was let to idle without rev'ing the engine on 2-3 sec intervals and would not start if it died. If allowed to cool for 4-5 minutes then it would start and the cycle began again. I replaced all the usual suspects, my Stihl service folks said that they were sure it was the coil because it fit all the symptoms of it. My 026 shut-off when hot only in idle not at higher throttle position including WOT.
Even though the service folks were certain it was the coil I did not believe it. After reading how to adjust the 026 carb settings in both the service manual and the owners manual (different methods/techniques) I adjusted the carb. Wow I had a new saw.
Ran great never died everything was fine. 15+ years later the saw still runs great, original coil still in it (the one the dealer wanted to replace).
3 bars and many loops have come and gone as well as filters and hoses. Bullet proof little saw. I don't know how your saw 'just shuts-off' but if my description is the same, try it. If it shuts-off at WOT then it is different and probably is the coil.
Deal with the simple before you go to the complex. The wise men in the designs dept of Stihl gave the 026 a carb that has one part that is totally unsuitable for a pro saw.
A plastic barb for the fuel inlet on the carburetor that has a habit of coming loose at times on its brass base.Running vibrations cause it to come a bit loose.Air is sucked in with the fuel, leaning out the fuel mixture while the saw is running under load. When this happens the saw stalls when the throttle is released.A proper carb setting cannot be done because of this problem.The remedy is to pull out the barb from its base, apply some epoxy glue and fit it back.To check if as loose barb is the cause, disconnect the fuel hose and see if the white plastic barb rotates on its base. I too was fooled by the notion that the 026 carb was a pig to tune till I figured out the usual cause of the trouble was this barb.A similar barb came on the Stihl blowers BR 320, 400, 420 etc.
Maybe not a complete rebuild at this stage. Just a cleanup until I get some advice from the great folks on here.
Bought an 026 Pro with the decomp, adjustable oil pump etc. Cost me a couple hundred Australian $$$ posted to me. It turned up and looked good. Bar has been dressed with a grinder and is not something I will use. I will have a go at fixing it up.
Put some fuel in it, pulled the cord and off she went. Badly out of tune, very rich and struggling to idle cold, but it ran! Shut it down and proceeded to strip it. Checked compression and got 175 psi. What would one of these saws register normally? Pulled the muffler and it was layered and clogged with carbon and oil and there is a black layer on top of the piston and lining the exhaust port. Its not thick though, just a thin film.
The rest of the piston and jug looks as new! The muffler is a no baffle unit and its got a fully adjustable carb. I think I know why it wasn't running well It was obvious while stripping it that it has never had a screw removed.
Its been bought and used and that's it. Not messed with or cleaned. The air filter has some splits in it so will need a new one. EVERYTHING is layered with oil clogged saw dust. I have picked most of this out with a screwdriver and plan to plug the motor ports and clean it up with degreaser and compressed air.
Under all the crap it looks great though. Once its clean the plan is to pull the jug and clean out the inside of the motor. I'm not taking it off till all the external crap is gone! The bearings feel VERY tight and the seals look perfect and show no signs of leaking so I am thinking I may avoid splitting the case and leave the bottom end as is for now. Next question.
Is it ok to just use some clean petrol to clean out the bottom end? Thinking I might even use some old 2 stroke that has sat for a while and is mixed with an oil I have stopped using. I just want to rinse it out and make sure there are no bits in there before I put it back together. I will lightly oil the bearings before I put it back together. For now.the only mod I plan is to make sure the jug ports are free of burs etc and do a muffler mod. Also going to fit a low restriction spark screen.
Will replace the 2 x oil lines, fuel line, impulse line and the front AV rubber bushing is stuffed. Going to order OEM parts as thus far my experience with cheap copy's is not good. They look the same but are made from inferior materials. Carb kit, re-assemble, tune and see how it goes. Will use if for a while before I go machining pistons flat and porting etc. I have been reading Now back to my earlier question on compression. If 175 is low for these I may get some new rings.
Should I bother or should I just clean it up and crank it? I will get some pics of the jug and piston tomorrow when I pull it apart. Third question. The Stihl manual I have doesn't list Idle and max revs. What should I be aiming for stock?
Looks like you're on the right track. 175psi is great for a stock saw. I wouldn't split the crankcase.
You're fine to rinse the crankcase with 2-stroke mix. I do it all the time on saws that need a new top end. I just pour it in, slosh it around, pour it out, and repeat until the fuel comes out without any discoloration or debris. Then I turn it upside down and let all the excess fuel drop/evaporate out. Just make sure to put a dab of oil and work that in before you put it all back together. I'd get new oil seals if it were me. The flywheel side WILL fail at some point.
That's a cheap piece of mind IMO. What model carb does it have? Brewz said: “ Funny.
I cant find any reference to a WT 394 in the Stihl part manuals?It's quite possible that your carb might have been from an MS260 or something and that's why you aren't seeing it for the 026 parts diagram. I swap carbs around on all my saws a lot. There's only slight differences between the WT series carbs used on these saws. The exception would be the WT-22B carbs that actually have a smaller carb throat than the others.
All the rest are pretty similar. (WT-194, -394, -426, etc.) Either way, the only things you would need for that carb come in the K10-WAT kit.
I generally just use the D10-WAT kit (diaphragms only) and then get the 5-packs of metering needles separate (either 75-75-7 or 82-75-7). This saves me a lot of money over time. Hi Gritz Really appreciate your help so far. I had a look at your porting job on the 026 and am thinking I might do a similar job down the track. I want the saw to be light but powerful.
I don't want 2 million RPM, just usable torque as it will be a work saw. I will pit it back together when all the new hoses I have ordered show up, and run it stock to see how it goes and get a base performance benchmark. I have been looking at carb kits and they all list a K11-WAT kit for the 026/260 carbs?
Is that different to the K10 you mentioned? I recon the WT 394 carb has been fitted so it can use new MS260 air filters. I checked the squish today and its at about.028 which is OK but I would like it at.020 A coke can is not thick enough so I will need to remove the stock gasket, measure the squish with no gasket and find some gasket material the thickness I need.
Stihl 026 Pro Manual
I got it all cleaned up today. The top of the jug and piston were lined with a thick layer of carbon. It looked like it had been starting to make carbon on carbon contact. Cleaned it all up and it should be a lot better now.
Piston and rings look good so they will go back in for now but all the oil grooves on the sides are gone so will order a new Meteor piston down the track. Cleaned out the muffler which was lined with tar like muck, gave the front cover the mandatory mod and fitted a new spark screen. I also filed the muffler flange face on the jug flat as it was quite uneven and causing leaks around the gasket under the muffler.
I polished it up after I took the photo which looks rougher than it is. Smoothed out the exhaust port and matched the muffler to it. While I was in the Stihl shop ordering the replacement hoses ($80 for 4 hoses and 1 x AV mount. They dont miss ya) I asked for a price on a replacement sprocket cover. That's almost what I paid for the entire saw? I will get a $20 Chinese special off evilbay as the original one has a hole in it. I would have been happier with an original one but I'm not paying $180 for a bit of die cast aluminum with 'STIHL' written on the side.
Pictures below. Stihlofadeal64 said: “ Careful on the squish on the 026.
Stihl actually makes a gasket to aid you in your quest - 1118-029-2306 (it is a.5 mm gasket) and with a new set of rings for your piston you should make plenty of compression. If you have an itch to buy new stuff for your saw I would look at a Meteor replacement piston kit. Not sure of their availability in your area of the world though. Looks like a nice project going on.Isn't.5mm the same as.020?
That would put him back where he started. Brewz, they make brass shim material that comes in multipacks of different precise thicknesses. I've used it a few time for that final squish adjustment.