I have a Garmen 178 Fish Finder / GPS.... It has been very reliable, never failed before in the 5 years I have had it.

Monday, A week ago at the lake, it kept dying 30 to 60 seconds after it is started. Repeatedly. I used my in-dash flasher instead for the trip.

When I got the boat home, I turned the Garmen on for about 15 minutes... turned it off and on... it ran fine. Ran it on simulator for a while. It ran fine, it never died.

Friday, took the boat back out. The Garmen did the same thing. Would run for 30 seconds or so, then itself power down.

This morning. I turned the unit on here at the house. It ran for 30 minutes without failure. I turned it off and on. I unplugged the power and sender connector... which appeared to be solid and correct. I checked under the dash where the power hook-up is, all seemed to be solidly connected.

I can't figure out why the unit runs here sitting on the trailer and for less than a minute at a time at the lake. I thought it might have been waves rocking the boat and a loose wire, but I also tried the unit while sitting in absolutely still water... the same result... runs less than a minute and then dies, poweres itself off.

Has anyone else had a similar problem with a unit?

Could be transducer going out. On the trailer not in water it's not loaded down. Just air for the sound waves to go through. But on water it has to push the sounds waves through the water, loading it down maybe? I've got a transducer for a Garmin 160c ,if it will fit u can use it to test with. Let me know