In this photo the second round of butyl is just about ready. You do not want to leave the butyl to thick here or it will squeeze out the OUTER edges of the trim ring and make a huge mess!


I had to redo my first port because I used too much butyl in.


EDIT: If you use a gray butyl tape like Bed-It Tape there is no need for the marine sealant!


You need enough to make a seal, and to squeeze out between the trim ring and the spigot, but not so much that is squeezes out the outer edge of the trim ring..