Head won't flush while underway

[Brian B]

While underway the head on our 25SC won't flush. It will not draw raw water for flushing. As soon as the boat stops after a few pumps I can get it to draw the raw water in without having to prime it. This is nothing new on the boat as it's been this way since we have owned it for the past year. It seems that when we are underway the engine is drawing all the raw water from the sea strainer.
Is this common? Any ideas?

 

[HRowland]

Hi Brian,

I have the same issue with the electric head in my R27. The engine produces a vacuum in the sea strainer at medium-high power settings. Since the head (and cockpit washdown pump) share the same strainer the head's raw water fill pump is unable to overcome the vacuum.

When the head is used and I am underway I reduce power (down to 1600 RPM or so) so a successful flush can be done.

Howard

 

[baz]

Howard: That's a real PITA situation.... :lol: One more reason to use the fresh water for the head as it has its own pump.

 

[Brian B]

Hi Brian,

I have the same issue with the electric head in my R27. The engine produces a vacuum in the sea strainer at medium-high power settings. Since the head (and cockpit washdown pump) share the same strainer the head's raw water fill pump is unable to overcome the vacuum.

When the head is used and I am underway I reduce power (down to 1600 RPM or so) so a successful flush can be done.

Howard

Ok that makes sense, as long as it's not just my boat.
I have never sat on the head long enough to ponder the issue while underway. :lol:
And yes there is always the fresh water option.

 

[knotflying]

Then there is also the Airhead option, no water at all! :lol: