You're asking for trouble with all of that goop on the gasket. I've tried several things to seal mine and old school hi-tac works fine without getting everywhere.

Simply stretch the gasket a little until it sits on the cover without pulling off. Next, paint the hi-tac on both the head and gasket bottom and let it become tacky. Set the cover down and install the nuts.

Rubber mallet or dead blow to the side when you want it off.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.