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Forespar 3/4" seacock engine intake

patrscoe

Member III
While I was preparing for my newly purchased 34-2 for spring launch, I notice that my engine intake hose was not reinforced so I replaced it this past weekend. While doing this, I also notice that the previous owner used a plastic 3/4" NPS to 5/8" hose barb at 3/4" Forespar seackcock, which seems to match the Ericson spec / manual as the proper hose and seacock size. This plastic piece (hose barb) seems to be slightly crushed and I would need to replace it. I have not found a Forespar product or similar tailpipe and I don't want to replace this with another plastic tailpipe.

Can I use a bronze tailpipe on a Forespar seacock?
It does not appear that Forespar makes this tailpipe, only 1/2" to 1/2" or 3/4" to 3/4".

Patrick
E 34-2
 
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Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Valves and hoses

Inn the late 80's Ericson was installing the then-new composite (Marelon) valves from Forespar (which was a line of products the company had recently bought up from the Aussie company RC Marine. My factory-installed valves actually had little "RC Marine" stickers on them.
EY was fitting these ball valves onto Marelon (r) thru hull fittings. There should be same-material tail pieces on each one. Ours had this.

I replaced all of those with the improved "model 93" Forespar sea cocks in the 90's. They are a LOT stronger, being a real "sea cock" with the valve integral to the flange against the hull.

After all these years, Neptune only knows what a prior owner might have done or why.

I will append some pix of the Forespar line just for reference.

Note that some folks are more comfortable with bronze sea cocks, and that's fine. Just be really darned sure that you get actual Bronze, from a trusted vendor. While there is a risk of electrolysis with any metal thru hulls, many owners prefer the metal over the reinforced plastic product.
Another case of more than one right answer....
:nerd:

Do keep the 3/4 inch hose if that is what the valve uses. I recall that we may have had to adjust the nipple size on the output side of our strainer to match the hose to the engine raw water pump. Sometimes those pump inlets might be 5/8.
 

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patrscoe

Member III
My hose is 5/8" and my seacock is 3/4", which matches the Ericson manual. They do not appear to make a 3/4" straight thread to 5/8" hose barb in a Forespar product line, that why I believe that the previous owner used standard plastic and not a Marelon fitting.
My question, what has everyone have done for this fitting and can I use a marine grade bronze fitting, threaded into a Forespar seacock?

Thanks
Patrick
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Go to the Source

My hose is 5/8" and my seacock is 3/4", which matches the Ericson manual. They do not appear to make a 3/4" straight thread to 5/8" hose barb in a Forespar product line, that why I believe that the previous owner used standard plastic and not a Marelon fitting.
My question, what has everyone have done for this fitting and can I use a marine grade bronze fitting, threaded into a Forespar seacock?

Thanks
Patrick

I would ask ForeSpar.
IIRC they do not advise attaching metal tail pieces to their composite valve bodies, but it's best just to ask them.
 

patrscoe

Member III
Might be a mood point. It appears that the threads on a Forespar is NPS but most bronze hose barb adapters are NPT.
Which explains why the previous owner used a standard plastic fitting to the seacock.

Patrick
 

toddster

Curator of Broken Parts
Blogs Author
Yeah, I was just searching through the Forespar site a couple of days ago. They say it’s OK to use a Marelon seacock with a bronze through-hull, so presumably the other side would be OK too, but all of their fittings are straight-thread. Tapered NPT won’t work.

Last summer, I was trying to find 5/8 fittings to fit Webasto equipment. Good luck. Where they’re even made, nobody likes to carry them. But hey, Bonus! A piece of that tubing worked perfectly yesterday as emergency vacuum hose replacement on the Jeep!
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
My experience is this is a common problem with the Forespar valves. Forespar doesn't make a large variety of tail pieces to fit into their valves, and when they do, there is another problem: Part of the strength in the Marelon valves is that they're made massively thick. So when they make thick tail pieces, the inner diameter winds up much smaller than it would be for a similar brass fitting.

However, since brass fittings are NPT and for Forespar NPS, the threads are technically not compatible. In reality, nearly every forespar valve on my boat had an NPT fitting screwed into it, whether brass or PVC.

I've had to live with this: A brass NPT fitting can work in a Forespar valve. Note, if you over torque it, you'll crack the valve, but with a reasonable amount of torque, the massively thick Forspar valve threads will tolerate the thread mismatch. Add some Teflon thread sealer, and you'll get a leak free fit.

A common way that Ericson ran the raw water intake hose was to screw a brass nipple into the top of the Forespar valve. The other end of the nipple was sawed off, so it was just a smooth pipe end. This pipe end would accept the 5/8" hose that ran to the raw water pump.

While not "perfect" or technically "correct," it's worked for the last 30+ years. This is one of the reasons I prefer to do this kind of work myself. You'll know where the potential weak links in your own boat are, so you can keep an eye on them.
 
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