whitfield profile 20 can't adjust air with dampner

[lpgreg]

I bought a 2003 Whitfield 20 last year and ran it all winter. It ran good even though the damper would only move 1/2". This year my Sommerset pellets are not dancing so I removed the exhaust motor and cleaned it out and the area behind it. I then cleaned the damper track and now have about 2" of damper adjustment and finally cleaned the stack. The inside was cleaned by removing the firebrick and tapping on the backplate to dislodge any ash. My problem is the flame does not change when pushing in the damper or pulling it all the way out. I am getting some clinkers and really cannot get the pellets to dance in the grate. Anything else I can clean or check. Thanks