Ms391 left on high idle

[Lupin_IV]

Ello. Disclaimer, I am not that mechanically adept. New guy started today, hes a dingle berry. he went to start a chainsaw and "let it warm up." He left it on partial choke and walked away. I turn the corner, see it smoking, and rush to turn it off. Strong burning plastic odor. Looked the chainsaw over at the end of the day, plastic had solidifies around the round disc that surrounds the sprocket. The starter chord will not pull at all. Any input on if there is likely internal damage as well? I.e seized piston or something? Or is it possible it will not pull because the melted plastic is preventing it from moving? My coworker and I theorized we may possibly be able to remove that rim and scrape away some plastic but were unsure. Any input appreciated.

 

[Reach]

That’s a new one! Usually an overfueled saw will just smoke and carbon up, not overheat like that! You could definitely try removing some of the problematic plastic, that might help. If not, call your dealer and see if he can give you any ideas.

 

[Rob Stafari]

Am I understanding this correctly, that it was left on fast idle with the chain brake on? That would most definitely burn up the clutch area(behind sprocket) on a 391. Could potentially do top end damage as well, depending on how long it was. Won't know more till you get it apart. I know of someone who left the chain brake on on a ms880 while attempting a stump cut with a big bar. Fried the clutch area and the top end. Needless to say, that was not a cheap date.

 

[Jehinten]

Sounds to me like it was likely the chain brake was left on.

I watched a guy start a saw one time with the chain brake on and then proceeded to rev the engine repeatedly until smoke was rolling out of the clutch cover. I ran over to stop him and he said "what? That's how you warm the saw up"

In his defense he didn't do tree work and had minimal saw experience. It was my first time working with him with saws, which is why I kept an eye on him to begin with.

 

[Lupin_IV]

Indeed, the chain brake was left on. We pulled it apart this morning and got it freed up a bit but it sounded a little off when we gently pulled the starter chord. The heat melted this small metal tensioning band (excuse my laughable terminology) right to that inner clutch area right underneath the sprocket. I guess we'll see once we get it put back together fully, but sounds like itll be headed to the dealer. Poor guy. The boss is a nice fellow but I dont think hes gonna like this :b

 

[Lupin_IV]

Thanks for the input, all.

 

[southsoundtree]

Chain brake band?



That guy sounds like a bullet to dodge.