lsaami
ArboristSite Lurker
- Joined
- Mar 12, 2023
- Messages
- 14
- Reaction score
- 6
Hey AS!
Love this community and all the helpful individuals here. I'm up against the ropes with this one. I acquired a few used Stihl saws from fellow who was offloading them, and they are WELL used (price was right). the topic of this post is a old-model MS391. It has served me very well for the last couple of years, but recently started having some issues. It start and runs great for the first few minutes, but after about 10-15 minutes of cutting firewood, it starts cutting out and has a lack of power, almost like it's running out of gas, only, it has plenty. Once it exhibits these symptoms, I cannot tune them out with the high jet. It makes no difference.
I was thinking it could be a plugged jet, but that shouldn't be affected by engine temp, should it? Maybe ignition issues?
I did a cold compression compression test this afternoon and it read about 105 PSI, so that was like punch to the stomach. Seems like that's really low? It's a brand new Chinese gauge, so I don't know how accurate that actually is.
Any Stihl wizards have some advice? Is this thing ready for the scrapyard?
Love this community and all the helpful individuals here. I'm up against the ropes with this one. I acquired a few used Stihl saws from fellow who was offloading them, and they are WELL used (price was right). the topic of this post is a old-model MS391. It has served me very well for the last couple of years, but recently started having some issues. It start and runs great for the first few minutes, but after about 10-15 minutes of cutting firewood, it starts cutting out and has a lack of power, almost like it's running out of gas, only, it has plenty. Once it exhibits these symptoms, I cannot tune them out with the high jet. It makes no difference.
- Spark plug is a nice medium brown
- once it fully cools, it fires right back up again.
I was thinking it could be a plugged jet, but that shouldn't be affected by engine temp, should it? Maybe ignition issues?
I did a cold compression compression test this afternoon and it read about 105 PSI, so that was like punch to the stomach. Seems like that's really low? It's a brand new Chinese gauge, so I don't know how accurate that actually is.
Any Stihl wizards have some advice? Is this thing ready for the scrapyard?