Stihl 026 Issues

[12guns]

A buddy of mine has an 026 that used to run great. I opened the muffler and tuned the carb as I have on my 026 and per instructions that are somewhere on this site.
So he has used the heck out of the saw as a weekend project saw. I'll admit it has had a fairly rough life in the back of his truck, but has been a great used saw. Recently he started having issues w/ it running under load. He "thinks" it may have run briefly on straight gas, but he then dumped it out now knowing for sure if it was mixed. Stupid I know.
So now it will start and run like a banshee, but it idles too fast and he says it doesn't have as much power as it used to. I tried messing w/ the carb H and L, but they don't seem to respond like they should, like my adjustment screws do. Any Ideas? Sound like a scored cylinder? Lower compression? Initially it seems to have good compression when I pulled the cord, but as it heated up it seemed weaker, but still "ok". Can a bad carb cause those issues? Thanks for any help, sorry I don't have more info, just thought this would be the place to start.

 

[Stihl-Pioneer]

Vac test the crankcase seals. Sounds like a leak.

 

[Stumpys Customs]

Sounds like an air leak fer sure. Don't run the saw till you git it figured out!!!

BTW what part of AR you from??

 

[Stihl n Wood]

I'll second that, just did crank seals in a husky 350. Sounds identical to the symptoms of this saw. Also this husky had appeared to have been hot a few times before. Or straight gassed. It would start and rev but had a fast idle and would not keep a tune. A say new piston and rings, and new gaskets and seals should be good to go. That's what this husky took. May not need piston but if you got it apart and going to go for the seals.....

 

[12guns]

Thanks for the help. I live a couple hours away so I'll have him stop by a shop to look into the possible leak. Makes sense, didn't even cross my mind!

 

[nmurph]

Pull the muffler and peek at the piston bf you do anything else.

 

[PogoInTheWoods]

I'll second that, just did crank seals in a husky 350. Sounds identical to the symptoms of this saw. Also this husky had appeared to have been hot a few times before. Or straight gassed. It would start and rev but had a fast idle and would not keep a tune. A say new piston and rings, and new gaskets and seals should be good to go. That's what this husky took. May not need piston but if you got it apart and going to go for the seals.....

I'll third that. The 026 is notorious for flywheel side crank seals going bad. While you're at it, go ahead and replace the intake boot, impulse line, and fuel line and filter. Make sure you get the right fuel line. There are two different sizes for the 026.

Good luck with it.

Poge