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Thread: My Garmin 498c sonar is on life-support.

  1. #1
    Member akjeff's Avatar
    Join Date
    May 2007

    Default My Garmin 498c sonar is on life-support.

    Looking for some sonar advice. Because, after a couple years of marginal performance (especially deep water) my Garmin 498c sonar is finally giving it up. The GPS works great. But absolutely no sonar performance over 250 ft. Marginal over 150ft. I'm using a dual frequency transducer and both 200k and 50k are failing equally. I am going to try a new transducer and see.

    I am also looking at upgrading to the Garmin 740s. Does anyone have any comments or opinions on the 740s? Any opinions on other DEEP water sonar units?

    Thanks in advance.

  2. #2
    Member Cap'n Ron's Avatar
    Join Date
    Jun 2007


    Wow....20 hours and no replies I have a Garmin 498 and haven't had any problems with the sonar when the transducer was positioned properly parallel to the boat bottom. Several times it got bumped out of position, with the trailing edge up, and then it would not work correctly, especially in the deeper water. Have you checked your transducer position? I can give you great advice on how to fill a set a waders trying to reposition it while still in the water

    I did have some problems with my Garmin 498 losing satellites, and also turning off for no reason. I sent it back to Garmin and got a reconditioned one for $160. That one worked fine. The original one was about 8 years old...

  3. #3


    If you decide to replace it, have a look at the Lawrence Elite 5. I'm about 10 for ten with guys who watch mine going out and buying their own. It's an amazing machine on all counts.

  4. #4


    I'll put a plug in fro the Raymarine 57D.. Pretty powerful machine for the price tag.

  5. #5
    Member SkinnyRaven's Avatar
    Join Date
    Feb 2007


    I upgraded to the Garmin 740S with radar from West Marine last year, will work with any Garmin transducer, so far so good, it does what it says it will.

    07 Ocean Pro 220 ET HT
    115 Yamaha
    Garmin 740S, GMR 18 HD
    Airmar TM 260-MM


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