what is the round thing in the front of my 02 260 bilge? it is black and has one wire coming out of it. i knocked it out while cleaning my bilge. the base sits in a 3 or so inch hole. after i knocked it out the water in the bilge drained into this hole. the boat was on its trailer so it did not go out the drain plug hole. i put the black thing with one wire in it back in the hole i knocked it out of. so what is it and do i need to try and seal it? it is under the front of the engine and VERY hard to get to.
thanks

depth finder sending unit

ya that makes sence, thanks
you think i need to seal it some how or is it fine as is?

Mine also popped out when my boat was relatively new. It's been a while and I don't remember what I used to seal it in with. I believe I just used silicone. Didn't want to use anything too permanant in case I had to get it out someday. I have had no problems since and it works well.

First clean out the hole good so the adhesive will stick. If it has water in it suck it out with a shop vac. Then use a towel to clean it out well. Then I wiped it out with thinner and re-sealed the transducer in the hull. Its tough to get down there but you just have to turn into gumby man and get it done. If you take off the fuel/water seperator it is much easier to get in there. I think it is located in the same place on your engine as my 502.

Understanding the merit of the suggestion for silicon or other softer adhesive, depth sounder transducers should be installed with a hard epoxy for best sonic performance. The goal is for the hull bottom to be as solid as possible so as not to distort the signal. Velocity removed the hull core material under the transducer toward this end.

I agree 100%.
Now that I think back . It was epoxyed in from the factory. Mine popped out after running in some rough water on Lake Michigan. Must have flexed the boat a little. The bottom surface was a perfect fit for the transducer as it had been molded in before. I got it as clean as possible, put silicone around the sides only and pushed it down as far as possible. Then put a weight on it over night to keep it in place as the adhesive set. I wasn't sure if the transducer had been damaged from banging around once it broke loose. I didn't want to make the repair so permanent that I could not get it out if the transducer was bad. I was lucky and it works great.

i plan to add a depth sounder this winter (don't have one)

Where is the best place to locate it? What is the best depth sounder out there, that shoots through the hull? I don't want to drill any holes.

thanks for the help, it does not look easy to get to.
i will be taking out the batterys it get to it thats for sure.

Ideally you want to mount it in the centerline of the pad area and well forward of the transom notch where the water is flowing smoothly over the hull (no turbulence/air bubbles etc.). Clearly the factory does this prior to engine installation so they can pick their spot! It's generally is in the front part of the engine compartment perhaps a foot or so back from the fuel tank bulkhead. Hopefully you can can access a similar location. You'll need to cut through the top layer of glass, remove the balsa core and then epoxy the transducer onto the remaining solid glass hull (since transducers don't work well shooting through balsa).

Not sure which depth sounder package to recommend as I've never had good service life out of any of them I've used.