Raw Water Hose

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Talisman
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Joined: 12/26/07
Posts: 243
Raw Water Hose

My Raw Water Pump hose to the Heat Exchanger looked beat up so I want to replace it while I install a new Oberdorfer pump.  While removing it I realized the hose is 7/8" and the nipple on the pump elbow is 5/8".  I looked at my old Sherwood and it is also missmatched at 5/8" so I have had this issue for the 12 years I've owned Talisman.

Is this a PO error or is there a rationale for this?  If it needs correction do I replace the nipple or arrange a two hose system with a 7/8" to 5/8" reducer?

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

pierview
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Joined: 9/27/09
Posts: 582

What you have is normal. Take the old larger nipple off the Sherwood and it will fit on the Oberdorfer pump. You'll have to shorten one nipple to get them to tighten down.

Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ

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rjwilson
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Joined: 4/28/14
Posts: 59

In the past two years I have replaced most of the hoses on the engine, but I couldn’t remember what the size was for the raw water pump. Got down to the boat today and I was surprised to see that the raw water pump inlet side uses a 5/8” hose while the hose to the heat exchanger is a 7/8” hose.  Seems Catalina likes 5/8” hoses, while Universal liked 7/8” for the raw water.
 

Bob Wilson
S/V Morning Breeze
2003 Catalina 36, Hull 2122
York River Yacht Club
Williamsburg, VA

Talisman
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Joined: 12/26/07
Posts: 243

So you have also been connecting a ⅞ to a ⅝ nipple on the pump?

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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rjwilson
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Joined: 4/28/14
Posts: 59

No, on the pump inlet side I use a 5/8" hose and on the outlet side I use a 7/8" hose.

Bob Wilson
S/V Morning Breeze
2003 Catalina 36, Hull 2122
York River Yacht Club
Williamsburg, VA

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Haro
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Joined: 11/7/14
Posts: 403

The output side is larger to reduce the back pressure on the pump. This is by design.

Talisman
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Joined: 12/26/07
Posts: 243

So Bob you use two separate size hoses with a reducer connection to attach the seven to five eighths?

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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rjwilson
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Joined: 4/28/14
Posts: 59

No, there is no adapter in the system. The pump inlet nipple is for a 5/8” hose and the outlet nipple is for a 7/8” hose.
 

Bob Wilson
S/V Morning Breeze
2003 Catalina 36, Hull 2122
York River Yacht Club
Williamsburg, VA

Talisman
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Joined: 12/26/07
Posts: 243

So I have been trying to get a ⅞ nipple from my usual trustworthy engine parts supplier, Hansen Marine, for weeks with no success.  They state it has to come from Westerbeke but they can't even get an estimated date from them.

This looks like such a standard item that should almost be available anywhere yet I have had no success.

Does any one know where I can get a ½ inch NPT x. ⅞ hose 90 degree elbow??

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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GaryB
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Joined: 10/26/08
Posts: 570

Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine

pierview
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Joined: 9/27/09
Posts: 582

Enrique.... take the 7/8 nipple off the old pump and screw it into the new pump. It will fit.

Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ

down_shift
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Joined: 8/16/14
Posts: 65

I just completed the bench work necessary to change the original ​Orberdorfer pump with the new style replacement Oberdorfer -- to grind the mounting flange (that small notch required) with a flap disk and swaped both hose nipples.  Didn't find a reason to replace the nibbles.  I did clean them by emersing in vinager with salt for the night.  They came out looking like new.

Russell Green
S/V "GoodwiII"  #759
1987 C36 MKI TR/WK M25XP
Moored: Deale, MD

True Wind
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Joined: 7/15/12
Posts: 139

I have noticed some water pooling on the floor in front of the galley sink when under way. Couldn't discover why that was. Today when I was working on the alternator I noticed that the Sherwood pump outlet hose (7/8") that goes to the heat exchanger had over the year been touching the alternator bracket and a tiny hole developed and it started to leak. The outlet hose is 7/8". 

2003 Catalina 36

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