I need to replace the shoot thru the hull transducer. What kind of epoxy have ya'll found to work the best? Also any tricks for removing the old one, or preparing the area? Thanks

i always used marine tex

Marine Goop

we use slow cure expoxy (24 hrs.) here at Humminbird.

Any ideas for removing the factory installed unit?

if its no good just hit it with a big o hammer..If your trying to save it, you will need to get something flat, like a flat blade screwdriver, and pop, or hit the driver with same o hammer..Clean the old area off with 320 grit sandpaper and lightly sand the bottom of new 'ducer, too.
make sure its level with bottom on boat..

I pulled one off once with a screw driver but be careful not to damage the fiberglass. It was originally put on with an epoxy that was kind of soft.

Thanks for the info.

You can usually get them to pop out. If you can get to the transducer, a long flat screw driver or even a tire iron can give you the leverage to pop it loose. Sometimes they just won't come out and have to just cut the cable and leave the puck. Just be careful not to pull up a big chunk of fiberglass.

Make sure to get all the bubbles out of the epoxy, before you set it.