I used 100% Clear Silicone from Home Depot when resealing the transom adapter on my boat. Been leak free since! Also, I got the stuff that is water safe in thirty min.
Anything at/below water line I only use 3M marine silicone. Some argue that its "difficult to remove" but I'd rather it be difficult to remove than have a leak. (note, dont use the 5200...)
I was wondering whats the best silicone to use I have a set back pump with custom plates so I don't want to get the wrong stuff.
In my best "grandad" voice with a cigarette hanging out of my mouth.... "if a day goes by and you learn nothing, I hope like hell you got a lot of sleep"....
Regular silicone from home d...GE 2 outdoor. Cheap and works well under water.