Hummingbird first finder

[Tuff guy]

I have a hummingbird piranhamax 230 portable fish finder and I am trying to decide whether it's worth keeping or if it's better to sell it and start over. I have used it a couple of times in la jolla with the suction cup mount without any real meaningful readings on it. I have a Hobie Kayak now, and would mount it in a better fashion. Are there any tricks to getting this thing to work, or for la jolla am I better off ditching it for a better model. Mainly I am trying to locate bait with my ff. Thanks!