One just needs to find a later saw.I would expect them to be sorted out at this point, I would think that if there are issues it would still be with earlier produced saws but wouldn't be the first time I'd be wrong.
The 2013 MS661 I had was trouble for the previous owner and then for me.
It had a bunch of warranty repairs and finally a full overhaul before I got it.
Then when I had it a crack was discovered on the Clutch-side.... leaked and would not run right.
I barely got a full tank through it and never got to fall with it... bummer.
Got it gone and found a 2016 MS661R.
The 2016 was a Great saw. Could see some changes.
The Clutch cover had changed. Everything seemed tighter fitting.
Subjective of course.....I would not worry about MS661 saws built after 2016.
If I get one big project I'm bidding on... I'll buy another.
Stihl should have field tested the MS661 longer.
I think they learned their lesson which is one reason why the MS462 is taking so long to arrive.