Depth Gauge Troubleshooting

[goclmbmnt]

I have a '94 Four Winns with a built-in depth gauge. The box under the dash says Lowrance LSM-1. From what I can tell from my online research, this is a special depth gauge that Lowrance made for Four Winns for a few years in the 90's. The depth gauge has never worked (I've owned the boat for about 10 years), but I'd love to get it working. The display just shows seemingly random numbers. Sometimes the depth seems like it might be right (based on nothing by eye-balling it) but most of the time it's all over the place. I haven't dug out the transducer yet, mainly because I'm not exactly sure where it is and I'm not excited about tearing apart my floor is it's the brains under the dash. Any tips or tricks to troubleshoot? I'd love to get this working and avoid a separate depth/fish finder mounted on the dash, but I guess that's the other option... Thanks!

 

[drrpm]

Re: Depth Gauge Troubleshooting

For what its worth, my depth gauge transducer is mounted on the stern near where the outdrive is. When it got knocked loose in its bracket it gave random readings. I'd start the search there.

 

[goclmbmnt]

Re: Depth Gauge Troubleshooting

I don't have anything on the outside or bottom of the boat. I believe it is a through-hull transducer. Was yours on the outside or inside? I suppose mine might be under the engine in the bilge... I've never really looked close down there.

 

[HalfFish5087]

Re: Depth Gauge Troubleshooting

Yes, its most likely far back towards the transom under the engine in the bidge. Should have a single wire leading to it and range in size from about the size of shot glass to a hockey puck.

 

[drrpm]

Re: Depth Gauge Troubleshooting

Mine is external and about 1/2 the size of a hockey puck.

 

[spdracr39]

Re: Depth Gauge Troubleshooting

My through hull was mounted close to the bilge pump and was doing the same thing. I tried to replce it and couldn't get the new one to read through the fiberglass so I mounted it on the transom and it has never worked better.

 

[goclmbmnt]

Re: Depth Gauge Troubleshooting

Thanks everyone. I'll stick my head down in the bilge and see what's there. Good to know that if its loose it might give random readings. Makes sense I guess.

 

[goclmbmnt]

Re: Depth Gauge Troubleshooting

Ok, I found the transducer in the bilge. It appears to be tightly mounted. Any way to test to see if it is working? Spdracr, did you just replace the transducer or a whole new setup? Are transducers interchangeable? Thanks!

 

[crabby captain john]

Re: Depth Gauge Troubleshooting

Transducers are not all interchangeable. If it is still tightly installed borrow a sonar like yours and connect it to see if it works after checking the wiring. Transducers rarely go bad.

 

[goclmbmnt]

Re: Depth Gauge Troubleshooting

So odds are the wiring has corroded or the "brains" of it under the dash went bad? I found a new one online for $50-75 but was hesitant to spend it without really knowing. But if I rule out wiring, I guess I might take the chance. I don't know anyone that has the same setup to borrow.