I have what I believe is a 77 Series OMC Control Box w/remote trim on my 85 Sylvan with an 85 Evinrude 90. The handle is cracked and causing the trim button to stick in the UP position. I have located another control box with a good shifter handle and want to swap the two but I can not get the handle free from the control box. I have removed the 'allen head' bolt from the back but I can't get it to come loose. Is there something more I need to remove?