Help me troubleshoot my depth finder install

[OldNBold51]

I needed to replace my 18 yr old lowrance 3500 with a working unit. Old unit worked fine until recently, then nothing. The new unit i chose was the cheapest out there, the Hawkeye D10X which has shoot thru hull technology. I'm afraid I might have went too cheap as the unit only seems to register some of the time. My 1st clue was during install/testing stage, hanging the transducer over the side in 2.9 ft water would only give me intermittent readings. I should have stopped there but i continued on and glued the 'ducer down right next to the old 'ducer with a slow cure epoxy. 24 hrs later, i take it out and I still get no readings under 3 feet. Over 3 feet, I'm get readings about 30% of the time , both on plane and sitting still in a 15 ft' depth cove. Unit will show proper depth for a minute or 2, then "_ _ _" for a bit, then back to proper depth.

Any ideas on how to cure this without buying a brand new unit or mounting below water line?

 

[OldNBold51]

Re: Help me troubleshoot my depth finder install

Update: I got this thing working well. My mistake was thinking just gluing it down next to the old 'ducer would be fine. it wasn't. i FOLLOWED THE INSTRUCTIONS this time by moving the 'ducer around in the hull till i found a spot yielding 100% full time signal. I epoxy'd it down and all is well.