Check valves in macerator pump throughhulls?

[backman]

I ( my crew) smoked one of my fishbox macerator pumps last trip. Its out; a wooden plug is hose clamped into the hose that goes to the throughhull which is safe at the dock, but marginal at sea.

Is there a check valve in those throughhulls to prevent siphoning?

[lowprofile]

No check valve.
I used a brass barb fitting with a threaded cap, when I had to replace my pump. I keep that fitting in my boat toolbox now.