Heat riser open stop

[KitCarlson]

I recent noticed that the heat riser in my 273 did not have a stop in the full open position. The bi-metal spring allows over travel, such that the damper would restrict exhaust flow. I fabricated a 3/4" x 1" tab from 10 gauge steel with a 7/16" hole in one end, that bolts to the exhaust flange using original outer flange bolt. It serves as a correct stop. Have I replaced a missing part? I know there is a stop tab on the closed position, was there one the open position, that perhaps broke off or was lost?

 

[KitCarlson]

I just found some rare and expensive asbestos covered tabs heat riser stops on ebay. I think a dab of high temperature silicone on the tab will work to quiet the stop.