eugene89us
ArboristSite Lurker
Hello, everyone. Have been lurking on these forums for a while. About a year ago, in March 2023, I purchased MS 261 saw with a carb from my local Stihl dealer. Manufactured in August 2022.
I have had to adjust the carb with a tachometer as initially had some issues restarting the saw when hot. Did the standard adjustment per workshop manual online, where you raise RPM, then find highest RPM with another screw, lower back, and lower some more to 2800 with L and LA (can't recall exact order, but followed perfectly). Since then, the chainsaw starts easily, hot or cold. Has not let me down. Burps on 3rd pull when cold, then fires up on second pull after that.
I was cutting down a fairly large red oak tree and felt like I really overworked the poor chainsaw. It was a large oak and diameter at the bottom approaching 40 inches (for a 20 inch bar on MS 261). Got a little worried that I could have maybe pushed it too hard. I kept my chain pretty sharp, maybe obsessively so, but had a couple of pinch points where saw started to produce fine wood dust for a minute or two before I repositioned. Worried I created similar conditions to running a dull saw. So i pulled the spark plug, which appears to be coffee colored as recommended (a little dark around threads), looked inside with borescope, and checked compression.
Once again, no issues running even after my oak struggle. Compression is around 165-168 psi when cold. Borescope still shows honing marks. What surprised me is seeing up and down darker lines. They don't appear to be scoring, just discoloration. If I shine light at them, I still see some honing marks over it, so if it is wear, it is not so deep as to remove all honing marks, but only a couple I can see running perpendicular. Is this some kind of precursor to damage or is this normal?
Of note, I ran first gallon of MotoMix (bought it for double warranty), a gallon with HP Ultra, and then switched to Red Armor per online recommendations. I am on my second gallon of Red Armor. So in total used about 4 galons of mixed fuel, cut down 2 giant oak trees and bucked for firewood, two smaller oaks, one hickory, and couple maples. Awesome saw. Use 93 octane ethanol free fuel. Got a Husqvarna oil and fuel combo can, so I get 5L of gasoline and mix 100mL of Red Armor for 50:1 ratio. But getting paranoid, maybe should have gone for M tronic version. Carb was supposed to give me freedom from dealer, instead now it worries me that I will somehow run it too lean and score the piston or cylinder. Any input on those lines in photo from the cylinder? Thank you!
I have had to adjust the carb with a tachometer as initially had some issues restarting the saw when hot. Did the standard adjustment per workshop manual online, where you raise RPM, then find highest RPM with another screw, lower back, and lower some more to 2800 with L and LA (can't recall exact order, but followed perfectly). Since then, the chainsaw starts easily, hot or cold. Has not let me down. Burps on 3rd pull when cold, then fires up on second pull after that.
I was cutting down a fairly large red oak tree and felt like I really overworked the poor chainsaw. It was a large oak and diameter at the bottom approaching 40 inches (for a 20 inch bar on MS 261). Got a little worried that I could have maybe pushed it too hard. I kept my chain pretty sharp, maybe obsessively so, but had a couple of pinch points where saw started to produce fine wood dust for a minute or two before I repositioned. Worried I created similar conditions to running a dull saw. So i pulled the spark plug, which appears to be coffee colored as recommended (a little dark around threads), looked inside with borescope, and checked compression.
Once again, no issues running even after my oak struggle. Compression is around 165-168 psi when cold. Borescope still shows honing marks. What surprised me is seeing up and down darker lines. They don't appear to be scoring, just discoloration. If I shine light at them, I still see some honing marks over it, so if it is wear, it is not so deep as to remove all honing marks, but only a couple I can see running perpendicular. Is this some kind of precursor to damage or is this normal?
Of note, I ran first gallon of MotoMix (bought it for double warranty), a gallon with HP Ultra, and then switched to Red Armor per online recommendations. I am on my second gallon of Red Armor. So in total used about 4 galons of mixed fuel, cut down 2 giant oak trees and bucked for firewood, two smaller oaks, one hickory, and couple maples. Awesome saw. Use 93 octane ethanol free fuel. Got a Husqvarna oil and fuel combo can, so I get 5L of gasoline and mix 100mL of Red Armor for 50:1 ratio. But getting paranoid, maybe should have gone for M tronic version. Carb was supposed to give me freedom from dealer, instead now it worries me that I will somehow run it too lean and score the piston or cylinder. Any input on those lines in photo from the cylinder? Thank you!
