I'm having a problem and hope maybe someone here can give me some advice. My pontoon boat came with a fish finder mounted already from the dealer. It works fine when I'm not running too fast say around 2000rpm but when I speed up it starts giving crazy depths and then the screen goes blank except for the temp reading. When I slow back down it will work again. The bracket is one of the kick-up type if you hit something and I thought maybe that happened. When I got it on the trailer it was locked in fine. Though it does have some movement in it. Could it be vibrating enough to give off a false reading at faster rpm's or does it need adjusting? Any ideas would be helpful. Its the Piranha 220 model.