I found my heat riser was pinned open, I thought it I had it pinned closed. I made a plate to block the exhaust flow, but it's .128" thick. I think it may throw off my alignment at the intake, and leak.

Has anyone built the better mousetrap for this one?

If you can't close the heat riser make the plate from 16 ga stainless steel. It'll survive. Or you could mill the attachment surfaces to align everything back up.

Thanks. Milling is not an option for me. A chunk of 16 ga stainless will be alot easier thanks.