Sticky Marelon thru-hull

[John Langford]

All the Marelon thru-hulls on "Calypso" turned easily except the large one for the engine raw water intake. So I backed off the four bolts that hold it together about a half turn each and the movement of the arm became smooth but still firm. Problem solved.

As I recall from taking one apart many years ago, the thru-hull is a sandwich of pieces of Marelon and o-rings that could easily have been assembled a bit too tightly. I am assuming that as long as the body of the fitting doesn't leak and the valve functions properly (i.e. stops water when closed and vice versa), then one can play with the optimal tightness a bit. I notice that Forespar warns against adjusting the bolts on its website but I am guessing that they are just trying to guard against some moron loosening the bolts to the point that the body of the thru-hull begins to leak water into the boat. Any views?

[RJ Randall]

I too have had to back off the nuts on the valves to loosen them up. I didn't know this trick until I took them apart for servicing.  In the two years I've owned the boat three of the Marlean handles have broken off.  The first to go was the galley sink. The second was the brand new one on the galley sink, six months after it was replaced. The third one was the engine intake, in the closed position of course.  To fix the intake I had to plug it from below and then remove and replace the valve.  This is not for the faint of heart.

My theory on the galley sink is that hot water may effect the valve.  That brand new one worked perfectly until immediately after the first overnight  cruise when hot water was poured down the sink.

Anyway, I now back the nut off a little when I start to feel too much resistance in the handle.