Enviro fire pellet stoves

I have an EF-III Bay i. In the last year I have done a thurogh cleaning, replaced both fans and all sensers. I have a good door seal and think the ash box is sealed? It has material all around it but it looks like the top had more material that is hanging. The slide adjustment is near full open and I still dont have good flow. (not enough air passage th keep the fire pot clear. The chimney is clean. If I add mild air into the intake it burns better but smokes. Does any onn know if this stove has a potentiometer for the exhaust fan? Where do I go from here??? Thanks for any help.