Bioburner
Moderator
I talked to tech dept at Harman about the stove with muffler today(they changed that idea). If you have replaced the muffler or it is clean the issue may be the seal at the hopper funnel mouth OR the lid is not sealing tight. Check the silicone at the bottom of the hopper. Check the seal and gasket on the top of the hopper. Can try and add a bunch of weight to the hopper lid to check the lid issue. Make sure the latch is pulling down snug too.