Hello I.m a newbe on boating. I have a 1984 imperial 120 merc. I'm blowing the fuse by the trim pump. It had a 7.5 amp fuse, and I replaced it with the same size. My trim sensor and limit switch is bad. It seems the trim will work until I go to the dock to trailer the boat. I use the trailer trim button and nothing no up or down. I check the fuse and it is blown. Reading some post it seems the fuses are 20 amp. The question is should mine be 20 amp instead of 7.5 amp. Thanks in advance for the replies.