Engine Seacock Increase

[Papawads]

I'm replacing 3-4 through-hulls and seacocks each year, in a move to high quality composites....

This year, the (I think) 22 year stiff seacock for the engine (Yanmar 4JH3-TE) is being done.

Anyone have any positive or negative views about increasing the through hull / sea-cock size? Clearly I don't have to, but the overall cost increase is not significant.

Yes, the sea-strainer, impeller etc won't change.

Thoughts
Papawads
:-)


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[milfordmattox]

Originally Posted by Papawads

I'm replacing 3-4 through-hulls and seacocks each year, in a move to high quality composites....



This year, the (I think) 22 year stiff seacock for the engine (Yanmar 4JH3-TE) is being done.



Anyone have any positive or negative views about increasing the through hull / sea-cock size? Clearly I don't have to, but the overall cost increase is not significant.



Yes, the sea-strainer, impeller etc won't change.



Thoughts

Papawads

:-)





View

Match the size of true design sea cock to you sea water strainer,my 4jh3 is all 1inch size hoses

[Kettlewell]

I recently replaced an old bronze through-hull and seacock with a Marelon setup and I had to increase the size of the hole slightly to accommodate the new one in order to maintain the inside diameter of the system. As milfordmattox said, match the system ID all the way to the engine. In other words, if it is a 1 1/4" ID hose that attaches to the engine, make sure you have a 1 1/4" ID strainer and 1 1/4" ID through-hull.

[Nicholson58]

Note that ball sea cocks might have a reduced port. Full line bore ball valves are available.

Also, FWIW, most old Groco and other bronze valves have a 1/8 inch plug between the ball seals. Screw a SS grease zerk in here to easily grease the ball.

[Papawads]

Thanks for the replies guys, which all align.

Nobody said why though.... ? Would be very interested to know.

My opinion could not be more humble. I thought the impeller would only be able to draw a certain amount of water through 2 meters of 1" hose, and having a 1" through hull to an open sea, vs 2" would make little difference to the suction pressure.

OTOH my little stainer gets easily clogged, and a 2" through hull and stainer would remain less of an obstruction.

But I have learned to be wrong with grace, and im very willing to again :-) thanks for any feedback.

Papawads

[jcapo]

I have 4JH-DTE with a 1-1/2" thru-hull and hose to a 1-1/2" Groco strainer with a 1" hose from the strainer to the engine. Total length about 6 feet. No issues for over 20 years. I just replaced all thru-hulls, except one that was new bronze last year, with Trudesign thru-hulls and valves.

My engine is below the waterline.

[Cheechako]

Originally Posted by Papawads

Thanks for the replies guys, which all align.

Nobody said why though.... ? Would be very interested to know.

My opinion could not be more humble. I thought the impeller would only be able to draw a certain amount of water through 2 meters of 1" hose, and having a 1" through hull to an open sea, vs 2" would make little difference to the suction pressure.

OTOH my little stainer gets easily clogged, and a 2" through hull and stainer would remain less of an obstruction.

But I have learned to be wrong with grace, and im very willing to again :-) thanks for any feedback.

Papawads

Going larger on the plastic seacocks may be a good idea as they might be sturdier. I had nothing but trouble with Marelon seacocks I had.

[DirtPete]

Originally Posted by Papawads

Thanks for the replies guys, which all align.

Nobody said why though.... ? Would be very interested to know.

My opinion could not be more humble. I thought the impeller would only be able to draw a certain amount of water through 2 meters of 1" hose, and having a 1" through hull to an open sea, vs 2" would make little difference to the suction pressure.

OTOH my little stainer gets easily clogged, and a 2" through hull and stainer would remain less of an obstruction.

But I have learned to be wrong with grace, and im very willing to again :-) thanks for any feedback.

Papawads

A lot of people have had very good experiences by trusting the technical folks at Yanmar.

What is the most frequent source of obstruction?

[Bowdrie]

Originally Posted by Nicholson58

Also, FWIW, most old Groco and other bronze valves have a 1/8 inch plug between the ball seals. Screw a SS grease zerk in here to easily grease the ball.

Those pipe plugs are installed as a means to drain the water that's in the thru-hole in the ball in freezing conditions.
With the valve in the closed position, you'd be simply pumping grease into the hole thru the ball.
With the valve in the open position, a few healthy pumps on a grease gun can easily rupture the valve body.
In neither case does any grease beyond some miniscule amount actually get applied to the sealing rings.
One must be very careful when using a grease gun on those valves.

[Papawads]

Originally Posted by DirtPete

A lot of people have had very good experiences by trusting the technical folks at Yanmar.

What is the most frequent source of obstruction?

White gritty stuff, assuming baby barnacles or something, but no expert (on this and many.ither things)