Before I can tell you what's wrong...
I need the answers to a few questions: Have you checked for a blockage in the tank vent line and eliminated that possibility? That would be the first thing to check, 'cuz especially at this time of year, those wasps known as dirt daubers love to build nests in the thru-hull...or it can simply have become clogged with dirt or pollen. Have you checked to make sure there actually is a y-valve or tee fitting in the pumpout line...that there's a pump or macerator in it, and that it's connected to a thru-hull? Assuming you've gotten that far, and so far no cigar...did you open the seacock on the thru-hull the hose is connected to? If you have a macerator, does it run, but just won't pump anything? If all the answers are yes, there's only one possible answer: the macerator needs a new impeller. You've been on a "no discharge" lake where you couldn't use the macerator, and macerator (in fact, any) mpellers "die" if the macerator isn't used...the neoprene dries out and becomes brittle, gets stuck to the inside of the housing, and the edges of the vanes break when you start the pump. Sometimes it'll work once, because the initial startup only cracks the vanes...the next time you start it, they break and the macerator won't work again till you replace it. If the pump doesn't work at all--no sound from the motor, either it's not getting any power, or the motor has frozen up from disuse. If it's getting power, replace the macerator...and always carry a couple of spare impellers for it. Two rules will prevent this sort of problem: 1. The time to check ALL the systems on a boat is BEFORE you leave the dock for the first time instead of waiting till you need them to find out they don't work. It's a good thing you only have a full holding tank and a macerator that won't work, instead of rising water in the bilge and bilge pump that won't work. 2. You can never count on equipment that's been unused for a long period to work.
