On my 9 SBL, mine has the star wheel, I'll stop the feed just shy of hitting the shoulder. I've never had the clutch to lock up and not dis-engage. One thing I recommend, is not to engage hard when engaging. Just gently engage the lever till it grabs and feeds. Not sure if the lever type is adjustable, maybe bac1972 can enlighten us a little.
Mine has the star wheel, so you are using the clutch to stop the feed?