Carver Owners Forum

New owner of 1985 Carver Mariner 3697, like so far, can anyone tell me if the boat has a holding tank gauge and if so where is it located and what size is the pump out adapter?

if you have a tank level indicator, It would most likely located in the head compartment. If you didn't see one you probably don't have it.
Your deck fitting will either be 1 1/4 or 1 1/2 FIP. Carver seems to have liked 1 1/4 for some reason. Most pump out stations don't have this size.

Do not believe that year had monitors unless it was installed after market by a previous owner. Also, you have a black water tank (toilet tank) and a gray water tank (sink & shower drain tank) that can be by passed and the grey water can be pumped overboard or into the grey water tank that can be pumped off.