SD40/50 seacock thread

[Captain Bill]

Going for a longshot here, but hopefully...... I was wondering if anyone knows what the thread is on a Yanmar SD40/50 seacock. Both of mine are frozen and they have always been a pain. I would like to replace them with proper ball bronze ball valves. I will be going into the yard in a couple of weeks and would like to replace them While I have the boat out of the water and it would really be nice to have the parts in hand before I start disassembly.

[dohenyboy]

New saildrive installation: SD50 - Multihulls4us Forums

these guys did it. maybe post there or send them a PM
or if you can go to the dealer, and ask to look at the part

[Captain Bill]

Nobody was able to help but now I have it off. For future reference the sail drive sea cock for an SD40 has 1 inch BSP threads. The adapter I got was not long enough to let the ball valve clear the bell housing so I needed a coupling and 2" nipple as well as the elbow and another nipple to make it work, but I now have a decent ball valve instead of the piece of crap that came with it. Parts cost me about $100 a side. It's tucked up against the engine under the starter so its really protected from impacts.

[Roosey]

I have Yanmar SD50 Saildrives on my Leopard 46 and the seacocks / watercocks attached to the saildrive were locked up since I bought the boat. I had spent hours working on them while in the water and only got a few turns on each one. I just hauled the boat last week and the yard suggested I disassemble the seacock and soak the housing in muriatic acid. I did this for 10 minutes and afterwards both seacocks work wonderfully, all for under $10. I plan to exercise the seacocks once a month and if they are getting stiff at all next time I haul for a bottom paint I'll pull them apart and do the same thing again.