Yanmar 2GM Intake Seacock (Kingston Valve)

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SailingTokyo

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The ball valve referred to in the Yanmar manual as a Kingston seacock needs replacing on my boat. It appears to be a 3/8" BSPP (British standard pipe parallel) thread on the inlet side, 1/2" hose barb on the outlet side. It's fused as a single unit and appears to be made of bronze, which matches with the bronze funnel shaped through hull strainer. The Yanmar manual shows the same valve used for both Yanmar 2GM and 3GM engines.

Here's a pic of the valve in the Yanmar manual: http://www.ss30.konnichiwa-japan.com/wp-content/uploads/2016/03/image-768x1022.gif

And a bit more info about this particular installation on my website here: http://www.ss30.konnichiwa-japan.com/replacing-throughhulls/

I can't find a manufacturer anywhere that makes this part. From what I can find, all manufactures of marine use ball valves (seacocks) with straight thread only make them as small as 3/4". Does anyone know of a source for bronze or compatible material (non-brass) 3/8" ball valves? What do other Yanmar owners use?
 
From What I understand the valve is not part of the engine and doesn't need to be a particular yanmar part. Mine isn't. If you can't source what you need then replace the through hull fitting and fit a new ball valve and hose tail.
 
SailingTokyo said:
The ball valve referred to in the Yanmar manual as a Kingston seacock needs replacing on my boat. It appears to be a 3/8" BSPP (British standard pipe parallel) thread on the inlet side, 1/2" hose barb on the outlet side. It's fused as a single unit and appears to be made of bronze, which matches with the bronze funnel shaped through hull strainer. The Yanmar manual shows the same valve used for both Yanmar 2GM and 3GM engines.

Here's a pic of the valve in the Yanmar manual: http://www.ss30.konnichiwa-japan.com/wp-content/uploads/2016/03/image-768x1022.gif

And a bit more info about this particular installation on my website here: http://www.ss30.konnichiwa-japan.com/replacing-throughhulls/

I can't find a manufacturer anywhere that makes this part. From what I can find, all manufactures of marine use ball valves (seacocks) with straight thread only make them as small as 3/4". Does anyone know of a source for bronze or compatible material (non-brass) 3/8" ball valves? What do other Yanmar owners use?
Click to expand...

ASAP supplies

http://www.asap-supplies.com/fittings-valves-strainers/valves-spares
3/8* bronze:
http://www.asap-supplies.com/fittings-valves-strainers/valves-spares/bronze-ball-valve-405722
 
Spyro said:
From What I understand the valve is not part of the engine and doesn't need to be a particular yanmar part. Mine isn't. If you can't source what you need then replace the through hull fitting and fit a new ball valve and hose tail.
Click to expand...

That's correct, the seacock is not a Yanmar part. The original valve was manufactured by Kingston. They don't appear to make the same part anymore. I'm looking for another manufacturer that does.

As you say I may need to replace the entire assembly if I can't find a valve that will work.
 
VicS,

Thank you for the link. However, that ball valve is not a compatible thread type, as it's a tapered, not parallel thread. Also it's not recommended for below waterline use, as noted in the valve's description.
 
vyv cox,

Thank you for sharing how your Yanmar intake is setup. If that is indeed a 3/8" BSPP throughhull to BSPT ball valve, does it appear to have a secure seating? How many turns does the valve go onto the throughhull? In theory the different thread types are non-compatible and won't result in a secure seat, but sometimes one gets lucky. If yours works I'll try the same setup on mine. Do you have a 1/2" hose barb on the engine side of the valve?
 
Paul06 said:
I've always thought that BSP sizes were the bore size. 3/8 BSP = 3/8 bore. 1"BSP = 1" bore?
Click to expand...

Yes, I believe that's correct. The internal diameter is 3/8", therefore the valve size is referred to as 3/8". It is indeed quite small, but as you can see in this picture from the Yanmar manual, it's the original, recommended part:
image-768x1022.gif


Furthermore, the internal bore of the water pump inlet and outlet are the same size, and the inlet hose pipe is 1/2", so all cooling water for the 2GM takes a fairly narrow course. As the actual amount of water flow for this engine is not very much this appears to be sufficient. The engine only generates 13 hp after all. Not exactly a raging powerhouse.

Fitting a larger, standard sized seacock such as 3/4" is certainly an option, however that would require both purchasing a new through hull, strainer and seacock and filling in then re-drilling the hole in the hull. The current cone-shaped strainer requires a 2" hole, which is much larger than I'd want if I were to change it all, as well as requiring prohibitively expensive parts. All in all it would be a lot of work and expense to change the current setup, so much preferable if I can find a replacement valve that works with the current through hull strainer.
 
To clarify my own mind as much as anything! My boat had a Bukh DV20 with a 1/2" skin fitting and seacock plus a strainer. I replaced the engine with a Yanmar 3GM30F and for the first couple of seasons kept the same inlet valve arrangement. It always seemed to run hot although the alarm never sounded. Later I replaced the whole lot with a 3/4" skin fitting and ball valve and a Vetus strainer above the waterline. That seemed to reduce the temperature and has worked well for over 10 years now. Sorry for earlier confusion.
 
The area and hence flow rate of a 20dia is 400sq mm a 15dia is only 225sq mm so you've doubled the cooling water, no wonder it runs cooler. The thermostat should control the temperature provided there's enough flow.
 
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