I have a New Helix 7 with regular transducer that I've been out 3 times with. It keeps losing botoom and depth - even drifting , motor off. It'll work a lil while then go 16-1-5-12-8-16 foot then stick on 1' with no bottom contour. I was in 16-24' today when it was doing it. It has a dedicated battery just for the fish finder and I charged it nite before each trip. GPS, mapping, water temp and speed all worked fine even when depth was acting crazy. I restarted it, reset it to factory defaults, switched to saltwater - no help.

Is the transducer mounted inside the hull or on the outside of the transom?

Transom mount

Might just be a bad transducer if everything is installed properly. Contact Humminbird customer service to see your options

I would get some pictures of the install on here and contact Information Wayne P.

I'm thinking bad ducer. I installed my first 2 Humminbirds on same boat with no issues.

I'm probally upgrade to HD ducer.......

Try setting the depth to manual instead of auto, my cores units would do this from time to time

I usually run on manual so I tried Auto - no help.

Does it ever show correct depth when on plane

Not last trip.

May have to contact hb customer service, it will to be late to get the upgrade to the hdsi tducer since the compact one is installed. If hb decides to replace the transducer you might be able to asking if they would be willing to work with ya on an upgrade. Is there any chance it got bumped and moved from previous setting. They can be real sensitive at times. How is the side imaging doing as far depth and clear picture

When depth is off Si Aint right either. When depth is right it looks Good.

Ok. The best way to trouble shoot it is to find someone that you can swap the head unit with. If you can't find anyone let me know