I've been trying out a 98 25HP tiller handle Mercury on my 14 foot boat. As it's going across the lake it tries to pull away and tries to turn right. I've adjusted the fin above the prop to the right as far as it will go. It helped a little but still tries to pull away. I've movied the motor back and forth on the transom but did not have any effect. Is there another way to adjust this motor so it won't pull away.