Yes that simple, and you can hear it running while turning the key. If it's not working and your valve is open, it will discharge while you are running at speed. You can get under your boat and have a look up at the valve to verify open or closed.

 

Excellent suggestions everyone - easy, went underneath - It's open

Turned the macerator key and did hear something running (sounds like a pump), but nothing came out on my driveway, not even a few drips
The holding tank shows empty but it has a few gallons of clean water mixed with bit of diluted anti-free in it. That said only let it pump about 5-7 seconds.

Not overly worried as I will not be using it, but more that the valve is open.

Sounds like the duckbill problem maybe ?

Thanks !

 

If the seacock is open and you can hear it running but it's not working, the duckbill valves are shot and need to be replaced. If the handle is vertical it is probably open.

Also, there may be a bronze square lock bolt on the seacock that holds the handle in place; if you loosen that you might have a chance of moving the handle and closing the valve.

 

For it to be open the handle must be inline with the hoses. Not necessarily vertical.

 

Seacock was open, and when I turn the key I can hear it running. But nothing came out Only thing is the tank level shown empty although I know it has a few gallons of clean water in it.
So guess it sounds like duckbill valves, or does holding tank need more in it.

I put some PB Blaster on the valve with a it of help from a pipe was able to loosen up then close the valve

Thanks or the info - 100% helpful