water issue when hot? certain hose?
 

1996 Mariah - Ok not exactly sure where the water sometimes comes from but sometimes when we run the bilge pump water comes out because it has water back there. The next time there is nothing. One thought is......could it be possible that a certain hose leaks when the boat reaches a certain temp? Are there hoses back there were only water runs through them when the motor reaches a certain temp to cool the engine?

It can sit there for a day and no water or even run it for a bit and no water. But then the next time there can be some water sitting in it. Maybe when the motor gets hot enough another hose kicks in and that is where the issue is?

Re: water issue when hot? certain hose?
 

What engine do you have? Whichever engine the cooling water circulates differently depending on the thermostat opening.
You should also have rubber bellows clamped to the risers that direct the exhaust to the out-drive. Check to make sure they are tight and leak free.
Have you run the engine on your flush muffs until operating temp? That might help you pin it down.
As an after thought, does it only happen when you have the on board cooler full of ice? Could it be melted ice draining into the bilge?