I have a 87 mercury 50hp with a 12 pitch prop on a 1987 Starcraft sfm160 aluminum fishing boat. The motor is set on the boat about 1/2inch above the bottom of the boat, looks to be in the right spot. I noticed yesterday that I dont have a straight roostertail it goes way to the right. Can anyone tell me what is causing this. All my other boat have had a straigt roostertail. Please help me with this. I want to get the best out of this boat I can. Thanks in advance Jayme...