raw water impeller replacement

brad minda

brad minda

.
Jul 27, 2015
50
catalina 30 SF bay
Headed out last Monday and noticed that water had quit coming out the exhaust. I haven't had the bottom cleaned in quite a while and I hope that's the problem. If not how do I replace the impeller and or clean out whatever might have gotten stuck blocking the water flow. I have an 85 with a universal 25 diesel. Up to this point the impeller seemed to be working fine.
I am having the bottom cleaned .

Brad
 
JohnVTX

JohnVTX

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Jul 14, 2015
840
Catalina 30 Stillhouse Hollow Marina
It is on the front top left as you face the motor. I have an aftermarket oberdorfer. You just need to get the right impeller and change out. Easy job.
 
Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Maybe not the pump. In the slip, I started the motor and had output. Backed out, but within a minute I could hear the exhaust telling me I had no water. Pulled back in slip, check impeller, water strainer was dry. Primed it, and all was okay. I think some trash in the water blocked the intake as long as it was sucking.
 
Justin_NSA

Justin_NSA

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Jul 7, 2004
8,481
Hunter 30T Cheney, KS
Check the strainer too. It might be plugged up. be sure that the thru hull valve is closed before you open the strainer.
 
dziedzicmj

dziedzicmj

.
Aug 13, 2012
533
Catalina 270 Ottawa
If i may add to the instructions - be double careful not to overtighten the (most likely) six bolts that hold the cover plate. They are usually bronze and they break quite easily.

Mdz
 
FastOlson

FastOlson

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Apr 8, 2010
2,091
Ericson Yachts Olson 34 28400 Portland OR
Your '85 boat probably has a Universal M25 diesel rated at 21 hp.
The raw water pump may be an Oberdorfer pump. Some folks report having a Sherwood brand pump, but I am not sure if yours might have one. Is there a little metal ID tag on the front of the cover, held on by one of the four cover plate screws?
As far as what "could" be wrong there are several places to trouble shoot. Start with the pump impeller. If any vanes are broken off, the piece(s) may be lodged in the metal elbow from the pump or in the heat exchanger.
Are the hoses, fresh and coolant, original? If so it's past time to re-hose the engine. Not very expensive by boating standards, but tedious. Been there/done that/did not get a T shirt. :)

While boat is out for bottom work, inspect the engine water intake -- if it has a "screen" remove it. They are problematic on their best days.
Your boat may have a strainer, or may not. Good to add one if there is not one there already. Plastic not so good for this, no matter how nice the picture looks on the ad. Go with a bronze base Groco unit. http://www.groco.net/SVC-MAN-07/Sec5/PDF/ARG.pdf

Loren
 
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danstanford

danstanford

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Aug 2, 2010
528
J-Boat J/88 Cobourg
Is there any way to check water flow if the discharge is not above water? Our 290 has the discharge way below the water line giving us no way to see how much water is being discharged. This spring we had an overheating problem and when I changed the impeller it was missing 4 vanes (only found 3) and the problem went away but I am always suspicious of the problem. The PO had an elbow welded to the discharge and a long piece of rad hose mounted to that which I never understood...but maybe it was so they could see the discharge by pulling up the hose. Would love a reliable way to check the flow but now I can only go down and put my hand on the intake hose after the raw water strainer and check to see if it feels cool.
Dan
 
brad minda

brad minda

.
Jul 27, 2015
50
catalina 30 SF bay
thanks to all the responses I had the bottom cleaned and guess what problem solved. have regular cleaning now scheduled.
 
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