circulating water

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Steve

My engine is not circulating water for cooling. The outgoing water is just a drip. Anyone had this problem? Thanks
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Probably need an impeller.

Steve: You probably need an impeller. What engine do you have?
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Check the system.

Steve: You really need to make sure that you do not have a blockage at your raw water intake first. Trace the system from the thru hull to the pump and make sure that water if flowing. The impeller is just a normal maintenance item. It should be replace every couple of years.
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Pretty basic.

Steve: Where is NPB (is that NewPort Beach, North Palm Beach?). Anyway. Basically it is a matter if getting the impeller and a gasket. Then you drop the pump and remove the cover. Remove the old impeller, install the new impeller. Remove and clean the surfaces for the gasket and replace the cover. Bolt the pump back up and adjust the belt. If you find that the impeller IS bad, you may want to consider having another one on hand in case this happens again when you are NOT in a position to plan for it's replacement. This is also a good time to replace your belts too. Save the old ones for backup.
 
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Alan Kibbe

Check for blocked raw water intake

My 1994 H29.5 raw water intake had plastic hose barbs which effectively limited the intake diameter to 1/4 inch. To check for a blockage, close the intake thru hull, remove the intake hose from the raw water strainer, and open the thru hull to see if water comes out of the hose. If it doesn't, you've got a clog between the thru hull and the strainer. I often had to unplug this hose twice a day if running under power. The fix is to replace the plastic hose barbs with bronze "full flow" hose barbs which will allow you to increase the hose diameter to 3/4". That way the crud that causes the blockage gets caught in the strainer rather than on the way to the strainer.
 
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Gene

Alan's right - check for blocked intake

Since you say there's a dribble of water, it's probably the impellor trying valiantly to draw water up through a clogged line. I had the same problem. Some sea grass got in the small section of hose (about 4 in) between the seacock and the strainer housing. When I finally got that little piece of hose off (it's a pain, since there's not much wiggle room), I found what looked like an old cigar packed in there. It was sea grass that got hung up on the plastic barb that Alan described on the strainer housing. But it's still a good idea to follow Steve's advice about the impellor and belts, too. It's easy to do. Check the archives. We've described it often.
 
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Terry

HI STEVE, BE VERY CAREFUL WHEN...

removing the small brass/bronze bolts that secure the impeller housing cover to the pump. The Yanmar on our H28 (2GM) had about eight of them. The heads have a tendency of shearing off due to age and corrosion. Pick up a few extras from your local engine (I'm assuming you have a Yanmar) repair shop before pulling the plate. I sheared two of them off; quite common. No big deal, vice grips removed the bolt once the plate was off. I used Teflon non-petroleum based lubricant on the new impeller and shaft. Also, make sure the vanes are bent away from the direction of rotation. You might want to replace the seal while your'e at it. You have to take the pump apart to do that, again no big deal. It depends on what you find. Terry
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Good Idea Terry.

and may I add to that. Put a little never sieze on the threads. This will make the R/R easier next time. These impellers should be check/replaced every year or two.
 
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Dan Rumrill

Circulation of cooling water

I did experience this on the boat that I just purchased. Intake is a 1/2" throughhull and was fouled by bottom growth due to inproper prep before bottom paint was applied. I hauled, replaced throughhull with 3/4" and took bottom down to gel coat and did it right. Problem solved. Dan R
 
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steve

It's fixed!

Thanks everyone. I have fixed the problem over the weekend with a help of a friend and took us about 2-3 hours to find it. The problem was very unique, it was not the impeller or heat exchange or any blocked pipe or intake. There is a little L shape fitting after the heat exchange which connect the pipe to the exhaust pipe was blocked. after unblocking it, a lot of black water came out and it works great.
 
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