Stihl 026 will not run

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Texan916

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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.
 

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Take it one step at a time, replace one part at a time and retest. It would be wise to take the front cover off the muffler and check the condition of the piston just to know what you are working with from the outset. We all recommend that a compression test and a vac and pressure test be performed on a saw before throwing parts into a saw but not everyone has the right tools on hand to do the proper tests. Visual inspections can tell one a lot, like broken fuel line and a bad impulse line, replace those and see how the engine reacts, the piston inspection does not cost anything and it can tell you a lot about the engine condition.
 
Take it one step at a time, replace one part at a time and retest. It would be wise to take the front cover off the muffler and check the condition of the piston just to know what you are working with from the outset. We all recommend that a compression test and a vac and pressure test be performed on a saw before throwing parts into a saw but not everyone has the right tools on hand to do the proper tests. Visual inspections can tell one a lot, like broken fuel line and a bad impulse line, replace those and see how the engine reacts, the piston inspection does not cost anything and it can tell you a lot about the engine condition.
Yes Sir. I have a compression tool. I will check around the local dealers for a vac tester or order one if needed. After work today, I will check the piston and post some more pictures. Thank you for the help.
 
Yes Sir. I have a compression tool. I will check around the local dealers for a vac tester or order one if needed. After work today, I will check the piston and post some more pictures. Thank you for the help.
Here are some photos I got of piston from exhaust side. Pulled impulse line as well and it is dang near new. I checked for leaks from the carb and impulse line connection and it is good. No leak and tight fit.
 

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Yes Sir. I have a compression tool. I will check around the local dealers for a vac tester or order one if needed. After work today, I will check the piston and post some more pictures. Thank you for the help.
If your compression tool is of the automotive type it will give a lower than normal compression reading, the Schrader valve spring in them are too stiff for a small displacement chainsaw engine. A two stroke small engine compression tester is more accurate, it has a white colored Schrader valve in the very tip that screws into the cylinder head. A visual inspection will tell me a lot more than a compression tester will and only involves removing two screws from the front muffler cover. I work on a lot of 026, MS260 saws and often find scored up pistons in the problematic ones, many caused due to bad seals allowing air leaks. The flywheel side crank seal is often the culprit damaged from overheating so often, heat caused from dull chains and owners forcing the saw to continue cutting, heat bulds up under the flywheel very quickly and takes out the seal lips.
Here are some photos I got of piston from exhaust side. Pulled impulse line as well and it is dang near new. I checked for leaks from the carb and impulse line connection and it is good. No leak and tight fit.
Yes, just as I had thought, that piston is badly scored, the engine will not run properly or for very long with a piston in that condition.
 
If your compression tool is of the automotive type it will give a lower than normal compression reading, the Schrader valve spring in them are too stiff for a small displacement chainsaw engine. A two stroke small engine compression tester is more accurate, it has a white colored Schrader valve in the very tip that screws into the cylinder head. A visual inspection will tell me a lot more than a compression tester will and only involves removing two screws from the front muffler cover. I work on a lot of 026, MS260 saws and often find scored up pistons in the problematic ones, many caused due to bad seals allowing air leaks. The flywheel side crank seal is often the culprit damaged from overheating so often, heat caused from dull chains and owners forcing the saw to continue cutting, heat bulds up under the flywheel very quickly and takes out the seal lips.

Yes, just as I had thought, that piston is badly scored, the engine will not run properly or for very long with a piston in that condition.
Thank you for the help and advice. The compression tool is an automotive one. I will add that to my list. I don't know if it is worth it to many, but being as my step dad bought this new many years ago, I want to fix it and keep it running. Silly to some I'm sure but sentimental to me. Any recommendations on a reputable parts website? If it's not too much trouble, what parts do you recommend?
 
Any idea on where I can find an oem new P/cyl? Is meteor or hyway any good? I will look at ebay as well. I will look at ebay. Any reputable ebay sellers you recommend?
 
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