Not a request for help, but this experience may help others.
Toilet has been completely serviced and valves and O rings etc replaced 2-3 months ago.
A couple of weeks ago just before leaving the boat to go home, we did the usual toilet trip before a 2.5 hour journey home. Did our 'Wees' and then proceeded to empty and then flush the toilet. There was no flushing sea water coming through, had to flush with fresh from the heads shower. Seacocks closed and as it was late decided to leave and investigate next time on the boat.
So back at the boat, used the toilet (after 2.5 journey lol). Opened the seacocks tried the flush and lo and behold it worked!??
Just thought that maybe the inlet had been blocked last time and then over time unblocked itself.
Toilet worked well for 2 days then the sea water inlet stopped again. Surely not another blockage. As I had serviced the toilet 2-3 moths ago I thought I would check the the valves at the top of the tube. When I opened it up there was a small (1cm) dead crab propping a valve open! Removed the bits of crab and put back together. The toilet was back working.
Posted so that if you get a similar problem where the inlet seems blocked, to check that there is no detritus preventing the little valves working.