Fishfinder Malfunctions

[RangerRob]

I purchased a slightly used 2004 Ranger 175vs with Yamaha 115 last summer and have had issues with the depth/fishfinders since day one. I have had boat back to dealer 1 time and they claim everything is fine.

This is quit long but felt all ( or most ) information is needed.

When boat was first acquired Depthfinders would not read accurately unless boat was at idle or trolling speed. Units would not read correctly on plane and would often just bounce off depths/reading for no apparent reason from 0-5 feet all the way to 350 feet and back - sometimes correcting itself. I have done some research on how they work and am aware of interference and also the cone angle. I contacted Garmin international and was sent a new shoot thru the hull transducer and that did not fix the issue. I was then instructed to send units back to Garmin for testing. I shipped units back and within a week had both units back and they were replaced with new ( or remanufactured ). Took boat out today ( was very windy BTW ) and right off the start the console unit jumped from 8 feet to 548 feet as I eased into the throttle. When boat was brought back to idle speed unit appeared to function properly again after about 5 minutes. I then tried to run boat at 5 mph and after moving a few hundred feet unit started to read incorrectly.

I am correct to assume that in good water unit should function at a fair amount of speed? Is there something I am doing wrong as far as settings? I have spoken with a few other boat owners and they say that they can run their boats on plane and their finders show correct depths.

BTW - I did for some reason check the fuse box last week and found that the fuse for the navigation lights was loaded with a 10 amp fuse ( should be a 3 amp ). I replaced fuse with 3 amp and when the boat was out today it started fine and ran fine for about 15 minutes and then after reaching location I slowed throttle down and engine would not idle. Fished for about an hour and when I got ready to leave engine would still not idle.RPMS were about 400 should have been 1000. I tried about 5 times and then swapped fuses - put 10 amp back in. Started boat revved rpms to about 2500 for a few minutes and then everything was fine. Ran  up and down lake 2 or 3 times and engine was o.k. Was this just coincedence or could this have to do with a ground or hot wire problem?

This has been very frustrating and disappointing to me especially being my first boat purchaseand the fact that it is so new. Any help or direction that someone can give would be very much appreciated.

Thank you very much

[George Welcome]

Transducer located poorly, is the probable reason for the poor reads. Air voids in the glass can cause this. ''

Engine problem sounds like a fuel flow problem, which could be from several things including dirty filter.l

[RangerRob]

The new transducer was placed in the same spot as the original from when the boat was manufactured. I assumed that it was the most logical being Ranger has been making boats for so long. Would it be possible that there is an air bubble located directly under the transducer or is it possible that there is just to much turbulence under my boat.

I figured that the fuel line may have gotten a piece of trash in but was not sure if the fuse being wrong could have been the culprit causing some sort of elctrical grounding or hot wire problem.

Thank you for replying

[George Welcome]

Their location does not mean its right - also perhaps the transducer was replaced previously; in any event it sounds like it has a void under it.

Fuse size would not alter running.

[Jig Man]

I agree that the transducer placement is the probably culprit.  You are shooting craps unless you grind out the top layer of glass and get to a good surface before putting the transducer down.

[RangerRob]

I removed transducer last week and spent an hour removing hoses and wires to be able to fit sander in bottom of boat. Sanded a 5 inch diameter spot 2 inches from the back of the transomand just off the center line of the boat.

Before I reglued transducer I taped it down with gorilla tape to see if readings would be in target or at least close. Readings were good for about a hundred yards and then when the boat planed the depth was off.

I figured this was close enough and I just reglued transducer in a few minutes ago.

I hope this takes care of it and I appreciate the advice and replies that were made.