2000 SR410. My main cabin head...

[SeaMax]

2000 SR410. My main cabin head pump cycles on for about 4 seconds every couple hours. I just replaced all 4 duck bills (wouldn’t wish that job on my worst enemy) but no change. The water in the head does not drop so I am certain the seal there is not leaking. There is a rubber grommet where the 1.5” vacuum line goes into the holding tank - sealing only by friction. I am wondering if anyone has had this problem and/or replacing the grommet on the tank fixed the issue.

[SeaMax]

Update - problem solved. Removed, cleaned and lubricated grommet going into holding tank. Must have been small vacuum lead there

[Johnruns]

I have the same problem on my 2001 SR410E after changing the 4 duckbills last month. I bought the rubber grommet but haven't replaced it yet. Someone suggested putting shaving cream around the grommet and fittings and it will show you the leak location (it gets sucked in at the leak point).

[PiscesPearl]

Had to replace the rubber vacuum hoses on my 2006 SR40MY that dry & crack after 10 years. Used as much pvc pipe as possible to minimize that future problem.

[SeaMax]

Johnruns- I suspect your pump and tank layout is the same as mine given the one model year difference. If so, you probably had to remove the vacuum line into the tank behind the pump to access the bolts holding the pump. That being the case, more than likely the problem is the grommet as was mine. I lubed mine with Vaseline before reassembling - all works well now. No indignity meant to those with impaired sight but I believe a blind person could be a good boat mechanic as many tasks (like removing the pump bolts) are done by feel rather than sight.

[DT227]

I had the same issue about a hear ago on a 2008 SR36SB. Duck bill valves were fine. A cross threaded elbow joint was the source of the leak.

[Livin_the_Dream]

Had a similar issue with frequent cycling and it turned out to be the gasket between the bowl and floor even though the water level was stable. Initially, I kept tightening down the bolts to the floor and eventually the leak got to the point where I was able to hear the vacuum leak.

[Airwaves]

Do moral of story - how many duckbills and seals can I proactively replace on my 1993 550? (2heads)

[SeaMax]

Have to make assumptions here which is usually not a good idea. However if you have the same Sea Land vacuum system as I have, there will be two duck bills on each side of the pump. One could be proactive however I would wait for signs of a problem before replacing, It is a nasty job and my original duck bills lasted 12 years.