Does anyone have experience on the macerator for a Carver 1986, 3207. Last season it would not pump out holding tank. Shore pump out emptied tank. Now I have filled forward holding tank with just water, to test macerator. The macerator pump seems to function, however, it does not empty tank. Any ideas, suggestions, fixes would be appreciated?
Follow the hoses from the tank. It sounds like you have a Y valve to switch between pumpout and overboard discharge and it's in the pumpout position. If there is no Y valve, then the pump is bad. If there is a Y valve and it's switched to pump out and you've been running the pump for many minutes than the pump is probably bad also.
Also, if the discharge is below waterline you will have a sea cock. Make sure it is open to discharge but close it and remove the handle (or zip tie it) to comply with uscg regs and avoid a fine if boarded What kind of pump? The cheap jabsco impeller style pumps get damaged if run dry. The bellow pumps (sea land) last much longer and can run dry. If you have one of these, check the duckbill at the pump inlet and outlet