Masterbuilt XL Propane - Mailbox Mod - Heavy QView - Need Some Help!

I have had this smoker for several years. I decided to do the mailbox mod to it. We use Todd's AMNTS 6 inch pellet smoking tube. If you have never tried one of these I would highly recommend it.

I got everything together and decided to give it a trial run. I lite the tube with some Pecan and got it smoking. I closed the mailbox door and was pleasantly surprised to see the smoker filling up with smoke. At this time there is no heat in the smoker. Smoke was coming out of the back vent just fine. This would be great for the times that I would like to cold smoke something with no heat.

I then turned on the burner in the smoker. That's when the fun started. I lost the draft. Smoke started to pour out of the mailbox. I opened the door to the smoker and the smoke started to come back into the smoker. I closed the door and smoke started coming out of the mailbox again. I found out that if I cracked the door a bit then all was fine. Smoke would then flow fine between the mailbox & the smoker.

I can live with cracking the door open, but any help would be appreciated on how to fix this problem.

Here are a few pics..


Here are a couple of pics showing how I have to crack the door.


This doesn't seem to lose much heat so I can live with it.


Here's a few pics of the mailbox mod.


There is a smoking tube lite in there. The draw is working good with the door to the smoker cracked open.



As you can see in these 2 pics the smoke is being transferred well.


Thanks for looking. I did warn you that this was heavy on the QView. lol

Phil