I installed my Garmin 546 with transom mount transducer a while back, but only recently mounted the transducer. I had it plugged in, but just sitting there. I would get readings this was, but I wanted to mount it in the hull like I have seen many do. I simply attached it to the inside of the hull using 4200. Now it will not give any readings... Anybody know what's going on and how to fix it?