I found this on ebay.....must be the later style muffler with a bracket
(broken link removed to http://www.ebay.com/itm/NEW-Muffler-Exhaust-With-Gasket-Bracket-For-HUSQVARNA-CHAINSAW-340-345-346-350-/290928016612?pt=LH_DefaultDomain_0&hash=item43bca93ce4)
(broken link removed to http://www.ebay.com/itm/NEW-Muffler-Exhaust-With-Gasket-Bracket-For-HUSQVARNA-CHAINSAW-340-345-346-350-/290928016612?pt=LH_DefaultDomain_0&hash=item43bca93ce4)
Has some valuable info on making sure you "Tune" the auto-tune correctly. Although it says to keep it in wood for 3-5 min (IIRC), this does bot mean continously. You can cut a 14" log, but dont hold it wide open until your in the cut.
Now we NEED pics. You know the rules Pen 
