I am having trouble with my depth finder at high speeds. It is mounted in back of the boat. When I get going at high speeds it stops reading the depth and goes blank. Is there any advice yall can give me? Thank you in advance.

Nope.

As far as I know, they all do that.

My Lowrance 322-C does that and it is an expensive unit.

I was told that air bubbles cause the readings to be off and you have to slow down to have the unit reset itself.

So don't worry about it but try to stay under 70 MPH to be safe.  

That's a problem typical of transom mount skimmer transducers.  Turbulence coming off the bottom of the boat at speed creates air bubbles which cut off the transducer from a solid reading.  You can move it around on the transom and possibly find a sweet spot but will only gain you a few mph before the signal is lost.  The best cure is an in-hull transducer.

Sorry for changing subject but i got a new 12; jon and was wondering the best place to mount the transducer?  Seen this clip to mount on trolling motor what do you suggest?

I have an eagle something, it is about 4 yrs old, mounted on the back of my jet boat and I don't have a problem with it not reading at speeds.  At least not up to about 35 or 40.  What I have found is that if you can mount it lower and into clean water that really helps.  I have mine mounted on a plate that I can slide up and down and I have found that mounted up where it would normally be on the transom I do get interference from turbulance but slid down as far as it goes, which is probably about 3/4 to and inch below where it would be mounted on the transom it is fine.

I don't have a single problem with my transducer acting up in my boat. My speed at top will max out at "55mph"-- so it says.

But so far no problems out of it.

-Nitroman