Stihl 026 will not run

[DP425]

the 44mm run better.

Really? Seems counter intuitive. Is it a timing or compression thing?

 

[Mad Professor]

Really? Seems counter intuitive. Is it a timing or compression thing?

Better ports.

 

[pioneerguy600]

So, in reality, it would likely be a bit of an upgrade. And those parts, OEM, appear to be relatively easy to get.

Now, I've seen it said that the displacement increase happened when it went from 026 to MS260... and I've seen it said that the "later" 026, or Pro 026's had the larger displacement.

What's true? Would my 1996-ish 026 Pro have the 44mm or 44.7mm?

Great info I'm getting here. Thanks all!

It would be debatable if the 44.7 is an upgrade over the 44mm but at least it would be new and OEM. I have several 026`s that have the 44.7 sets in them and they have been running 5 -7 years without problems, they all have lots of hours on them mainly used for hardwood firewood work. The only way to know for certain what P&C is in your saw is to measure it, years of production and serial number change overs have been disproven many times. All the MS 260`s I have worked on have the 44.7 sets, I never came across a late model 026 that had them. . There have been posts from others saying that later model 026`s may or may not have the 44.7 sets.

 

[wildwes]

With a late 026 you could have either. If the saw has had a new top end in it's life, it could have either. You need to measure to know for sure. The 44mm seem to run better stock, but with work the 44.7mm can run very well too.

 

[stihltech]

Watch what version carb and muffle you have. Single adjustment screws need more exhaust flow to run correctly stock.

 

[Doug H]

I just finished rebuilding an 026 that I got in a trade. I paid $200 for a really nice 025 that only needed carb tuning and a good cleaning and the 026. It had low compression and no carb at all. I removed the muffler and the piston skirt was medium scored but the rings were free and the upper cylinder on the intake side looked good. I checked in the spark plug hole and the exhaust side looked pretty clean. I took the carb off of my 024 and fired it up. It rattled like a baby rattle on idle. When the cylinder came off, the piston was 1 mm smaller on top and 2 mm undersize at the bottom of the skirt. The cylinder was lightly scratched below the exhaust port, but really clean everywhere else with no aluminum transfer. I was able to lightly sand out the scratches with 400 grit emery cloth and polish the ports, but not the transfers (too hard to get to). Since I'm cheap and OEM P&C kits cost $300+, I ended up buying an aftermarket piston kit for $8.59 delivered. I ground some flash out of the piston ports and then it looked just like OEM. Cleaned and installed it all. Started in a few pulls. When the aftermarket $15 carb kit arrived, I installed and adjusted it slightly. Saw starts, idles and runs great with good compression. Now to see how long my $25 rebuild lasts.

 

[Mad Professor]

I just finished rebuilding an 026 that I got in a trade. I paid $200 for a really nice 025 that only needed carb tuning and a good cleaning and the 026. It had low compression and no carb at all. I removed the muffler and the piston skirt was medium scored but the rings were free and the upper cylinder on the intake side looked good. I checked in the spark plug hole and the exhaust side looked pretty clean. I took the carb off of my 024 and fired it up. It rattled like a baby rattle on idle. When the cylinder came off, the piston was 1 mm smaller on top and 2 mm undersize at the bottom of the skirt. The cylinder was lightly scratched below the exhaust port, but really clean everywhere else with no aluminum transfer. I was able to lightly sand out the scratches with 400 grit emery cloth and polish the ports, but not the transfers (too hard to get to). Since I'm cheap and OEM P&C kits cost $300+, I ended up buying an aftermarket piston kit for $8.59 delivered. I ground some flash out of the piston ports and then it looked just like OEM. Cleaned and installed it all. Started in a few pulls. When the aftermarket $15 carb kit arrived, I installed and adjusted it slightly. Saw starts, idles and runs great with good compression. Now to see how long my $25 rebuild lasts.

WTF?

1mm and 2mm clearance piston clearance. You running a 44mm piston in a 44.7mm cylinder? Even then those measurements would be bad..........

 

[wildwes]

WTF?

1mm and 2mm clearance piston clearance. You running a 44mm piston in a 44.7mm cylinder? Even then those measurements would be bad..........

I don't know how that would even have enough compression to fire...

 

[Kyfred]

Recently my step dad took his Stihl 026 into the dealer due to it not cranking or popping off. The dealer told him it has an internal issue and it cannot be repaired. I went to visit them last week, he told me about it and I told him it can be fixed. Parts are still available. He said I could have it and would like to see if I can get it running. After first inspections and several pulls with nothing, I pulled the muffler and plug and inspected the cylinder. It was bone dry with no fuel reaching the cylinder. The plug was dry also. Initial thought is fuel delivery issue. Upon further inspection, I found the fuel line was nearly broke in half. I pulled the air filter and carb. I disassembled carb to find it dry as well. However, the filter and carb were very clean, not clogged and no debris. I went to my local dealer to get a fuel line. Of course they didn't have one but had the fuel line to a ms260 I believe. It was slightly longer. I got 2 of them. A little trim and it fit perfectly. Reassembled, added fresh fuel and was able to get it to pop off on full choke. Moved to half choke, got it to run for a rew seconds then die. Not able to get it to run for more than a few seconds at half choke and will not run at all with no choke. Checked spark and it is very strong. Checked and cleaned fuel tank, checked tank filter and vent. Filter was great but vent definitely needs to be replaced. It has the felt-like cone vent but I'm struggling to find one. I noticed there are a few different tank vents for this saw ( I assume due to the different years it was manufactured and slight upgrades) so is it possible to replace with a different style from the 026 saw line? My next part to replace will be the impulse line as it seems to be expanded and worn at the carb. Looks like fuel is leaking slightly at that connection. Have that on the way plus a carb rebuild kit, all from Saw Again Parts. I believe she still has a lot of life in her but am a little stumped at the moment. Any ideas or suggestions to get this fine dime back in working order? Also, thinking about ordering several extra parts ( fuel lines, flywheel, meteor head/piston and ring kit, new plastics, pull cord and spring, bumpers, etc..) for this saw to have on hand down the road as it seems they are getting more and more difficult to find certain parts.

On my 026 every few years had to put a diaphragm and fuel filter due to what I was told was ethanol in the gas. I use mine when fixing fence and is not used every day. 4 yrs ago I had a new carburetor and fuel filter and use the marine sta-bil ( blue stuff) in the gas when getting and mixing new gas and so far no problems . I’d say any ethanol treatment would work . I’m trying a can of premix gas in the saw now and so far it runs fine