ECO65 DROLET not burning at full potential

[Mrs.Firewood]

I have had my eco65 for 2yrs and this year I am having problems with extra smoke smell in house and pellets building up . This is a 2011 so the pellets do not drop into the pot but pushed forward. I thought it was the pipe so I shorten it outside! The glass also blackens out quickly. Accepting all suggestions...
Yes I clean the stove and pipes thoroughly.
Thank you in advance ☺

 

[johneh]

Sounds like you have a combustion air problem
or did you change pellet brands?