Does the water start entering your hull as soon as you switch on the livewell?
Or is it after the livewell is full?
It’s possible you have a cracked fitting or hose on the overflow drain. Make sure you go after the right problem. If leak occurs when livewell is full, look at drain or overflow.
Also, before you tear up the whole floor, see if there is any way to inspect the hose right at the inlet to the livewell and also at the livewell pump back at the transom where the pump connects to the hose. You may just have blown a hose clamp or broke off the pump outlet nipple. Most freshwater boat makers use cheap pot metal clamps that rust out on these fittings so check that before you tear things up on the floor.
If you’re lucky you have a leak right at the pump or the inlet fitting that can be changed without tearing up the whole floor.
Always use stainless steel clamps in all marine applications and always double clamp every connection if there is room.
Grouse