My depth sounder flits on and off randomly giving me a depth reading about 5% of the time. Bought a new Faria unit, wondering if anyone out there knows if there is any coring material under where the transponder mounts below the cabin door (in a 1998 29 stepped hull). Fountain mounts it here so wondering if there's no coring here, or it's just the best place they could put it and THAT is why it flits on and off, due to the coring, not because my old sounder is bad. In addition, my oil pressure guage randomly shoots up to like 80, then sometimes randomly goes back to like 40 while under way, not necessarily maxing out RPM, just cruising along 38-4800, but seems to stop going to 80 and return to 40 if I just turn engine off then back on, but that solution is random too. Anyone have any experience with this in past. Guages are whatever was standard on this model, boat is stored for winter so I can't recall what brand they are, sorry.

Not sure of the answer on your depth sounder.. the oil pressure gauge problem sounds like you might want to replace the sender..

I have a Garman and I think I read it had to be to the rear more and must not come out of the water. Check on line Garman's site for instillation instructions.
Rich

I replaced my transducer under the cabin step and it works fine. I think they put it there so it can always get a good reading and not mess up because of aeration from step.

In order to run cable to dash u must pull off Ulpolstry around door.