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Still sorting out not-quite-purchased boat. Just not getting much water out exhaust. And water pump housing too hot to hold in operation. Mechanic assures me the housing should be cool as it sucks in 50° water. This is a brand new Sherwood pump. Boat isn't close by so I'm relying on broker's mechanic (nor do I have any real experience). Engine rebuilt 6 years ago.

Seems to me that there was some reason (unavailable) PO put new pump on in first place ... and that issue has yet to be resolved apparently. Doesn't this situation scream of a blockage in water passages, plugged ex elbow or a collapsed hose?

Thoughts welcome.

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My diesel (Universal M25) had a lackluster flow out the exhaust, accompanied by a propensity to creep upwards of 185F over time.

I pulled the intake hoses and found that they were undersized (1/2"), and half-blocked by accumulated crud.

Replaced them with new 5/8" flow is healthy and temp stays right where it should.

If that doesn't solve your problem, follow the path.  Is there a raw-water strainer?  If your boat is like mine, the next things to check are the hoses to/from the heat-exchanger, and the heat exchanged itself.  Then the exhaust mixer. 

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Thanks guys. Mechanic says all working correctly now. We'll see. I've read a whole bunch on line about this simple system. I've run into the bad hose thing once before. I found a spare impeller aboard ... a positive sign of some maintenance.  

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23 minutes ago, SloopJonB said:

So what was the problem?

Won't know til Monday. I'm hopeful but I've been on the planet too long to believe a breezy "it's OK now." Will advise. There were couple of issues. In the ensuing investigations I've run across several mods to make right away. Not moving back aboard til Spring.  

Post was really to confirm that WP should be cool in operation. Seems obvious but ...?

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Check inline strainer. and make sure handle on screen is not in line with inflow/outflow.

I have had a family of tiny muscles trying to breed in the strainer and kill my water flow late in the season.

If there is a Groko strainer prior to the pump, see if the cap has a cork washer under the lid.  If so, replace with a rubber flat washer from hardware store for less than a buck.  The cork ones harden over time and induce air leaks which can have a big impact on water flow as that pump is trying to suck water..

 

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Here's a tip- those Sherwood pumps suck. I discovered that the Moyer aftermarket raw water pumps for the Atomic-4 bolt right on.

That's what I use.  Moves a lot of water. 

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Well, mechanic said all is good with limited water flow ... ie, he couldn't make the engine overheat. Anyway, I own it now. Next time at boat I'll be looking for these issues and popping for a high dollar intake hose. 

On 1/10/2021 at 4:56 PM, Foreverslow said:

Check inline strainer. and make sure handle on screen is not in line with inflow/outflow.

I have had a family of tiny muscles trying to breed in the strainer and kill my water flow late in the season.

If there is a Groko strainer prior to the pump, see if the cap has a cork washer under the lid.  If so, replace with a rubber flat washer from hardware store for less than a buck.  The cork ones harden over time and induce air leaks which can have a big impact on water flow as that pump is trying to suck water..

 

And continue on from there. 

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4 minutes ago, DrBrewHaHa said:

I had a 4511 in a Catalina 30 and it never pushed much water. I never had a problem with temperature. Nice simple tractor engine and worked well. Easy to find parts for mostly.

Thanks. I've been all over the net and read several comments like this.

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Some of the mixing elbows are ported with relatively small holes around the ID easy to check if fouled, also doesn't take much to foul a small shell and tube heat exchanger, would be more heat and low flow.

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The 5411 is the early engine with no heat exchanger.

The new water pump is the clue.  Whatever caused the PO to put new pump on hasn't been remedied. The pump is hot to touch. If it should be cool ...

I really hope it's something simple like that cork washer mentioned above. 

 

 

 

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10 hours ago, ziggy said:

I don’t recall, but I’m thinking it’s probably warm from the rotation of the impeller and also being mounted on the engine

Yep. Gots to be warm. Mine is apparently hotter than that. Thanks. I'll be starting on that problem soon. 

 

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