I ended up changing the trim pump and the problem stopped. I think BUP was right it had to due with the filters in the bottom of the trim pump tank, but I broke the original mounting for the OE tank when taking it apart. I replaced with one form SEI marine like this. Not saying this will solve your problem, and I would really have some who's know fiberglass repair look at your transom.


I will also say it didn't last but a few years, and I replaced it with another SEI. I think ideally I should have used the Merc Pump but @ $1k+ I passed.