Useless fishfinder when motor is running.

[tkite16]

   I have a Hummingbird 595c fishfinder on the console of my boat.   When I'm running with the big motor the GPS side works great but I lose the ability to see the depth. It will read that the water is like 900 feet deep.   I just used the same mounting braket for the transducer the last owner used on the back of the boat.

   Im assuming the problem is motor noise.   Anyone know of a way to get it to work when im running? Will it help if I move the transducer to the extreme outside corner of the boat in back?

  Any help is greatly appreciated.

[CGH]

Check your connections and make sure all are tight.   Move your transducer as far away as possibe from your main motor as possible.  Check the bat connections on both the Unit and the outboard.

[Wayne P.]

If it works fine when sitting still, then you probably do not have the transducer mounter correctly. The bottom half of the transducer should be below the deepest part of your boat hull and should be close to the centerline of the hull also to get readings while underway. If it is mounted correctly and you get interference, move the transducter cable as far from the boat wiring as you can. Are your spark plugs the resistance type?

[cart7t]

Your problem is not motor noise but turbulence and air bubbles running across the face of the transducer while your underway.  The only way to correct this is to find a spot on the back of the transom Where it will pick up correctly.  Any kind of hull strake or a rivet, if it's an aluminum hull, can produce enough turbulence to break the smooth flow of water across the transducer.

You could also try an thru the hull transducer if you've got a fiberglass boat.

[Glenn]

Your problem is not motor noise but turbulence and air bubbles running across the face of the transducer while your underway. The only way to correct this is to find a spot on the back of the transom Where it will pick up correctly. Any kind of hull strake or a rivet, if it's an aluminum hull, can produce enough turbulence to break the smooth flow of water across the transducer.

You could also try an thru the hull transducer if you've got a fiberglass boat.

Ding! Ding! Ding!  We have a winner!  This is the exact answer I was going to post.  Externally mounted transducers don't work very well, if at all, while underway using the big motor.  Cart7 explained the reasons very well.

[Catt]

Your problem is not motor noise but turbulence and air bubbles running across the face of the transducer while your underway. The only way to correct this is to find a spot on the back of the transom Where it will pick up correctly. Any kind of hull strake or a rivet, if it's an aluminum hull, can produce enough turbulence to break the smooth flow of water across the transducer.

You could also try an thru the hull transducer if you've got a fiberglass boat.

Ding! Ding! Ding! We have a winner! This is the exact answer I was going to post. Externally mounted transducers don't work very well, if at all, while underway using the big motor. Cart7 explained the reasons very well.

There you have it  

[fishfordollars]

If you mount the transducer inside the boat make sure you use the correct two part epoxy are you will still have problems

[tkite16]

  Thanks for the input guys , so do i need a new transducer or will the one that came with it work?  Also can i mount it in back by the gas tank.   And if yes to all these what kind of 2 part epooxy? :-/

[NBR]

Assuming you have a stepped hull mount the transducer in the back close to the transom and centered in the boat. Make sure you leave drain plug clearance if you use or ever might use an inboard fastening plug.

Mine has been in that spot for over 15 years and works fine up to about 50mph and 130 feet of depth.