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GT 40 Sherwood water pump

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tjca77 View Drop Down
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    Posted: April-29-2023 at 7:31pm
How can I tell if my water pump is broken? I had my impeller installed upside-down and am concerned it is broken. Reinstalled correctly and still no cooling water. Boat is on a lift in the lake.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bwinn Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2023 at 10:16pm
TJ,
How long was it run backwards? Did you peak at the impeller before you reinstalled it? It may have burned up from running dry. Some times the blades of the impeller can look ok but the rubber body will slip on the brass hub causing overheat.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tjca77 Quote  Post ReplyReply Direct Link To This Post Posted: May-01-2023 at 7:02am
It ran backwards for less than a minute. I pulled the impeller and confirmed the blades are intact. I didn't notice the body slipping on the key. I will pull again and check.

I read a previous thread on here indicating it was easy to burn up the water pump, and that combined with the fact that the second install with the cam screw pointing towards the oil pan also failed to suck water has me concerned.

I spoke with Nautique Parts yesterday and they suggested revving the engine to get the pump to suck water? Is this common practice? I have never had to do that before and do not want that to become common practice.

Thanks again for the help and suggestions.
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KENO View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-01-2023 at 7:43am
I'd probably .......

Take one end of the suction hose off (like back at the suction strainer or the inlet to the transmission cooler), 

Fill it with water so the pump will prime easily, hook it back up,

Make sure all the suction side fittings, strainer O ring and housing are tight and 

Start the engine with a quick blip to a couple thousand RPM and see if things start flowing

Sometimes a prime is needed if the suction line was completely drained


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Post Options Post Options   Thanks (0) Thanks(0)   Quote tjca77 Quote  Post ReplyReply Direct Link To This Post Posted: May-01-2023 at 9:05am
Thank you, will prime everything on the suction side and reconnect. I also have a new impeller on the way, just in case. I need a spare anyhow.

It is going to be a few days before I get back to the lake, just want to have any parts I might need before I go. But don't want to throw money away on uneeded parts.

Like I mentioned before the cooked water pump comments have me worried. Thanks again.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote tjca77 Quote  Post ReplyReply Direct Link To This Post Posted: May-14-2023 at 9:55pm
Good news, got the pump primed and it is pulling water. I filled the the hose off the bottom of the water pump till water came out of the intake on the hull.

The not so good news is I still have a drip at the water pump housing. Is the next step a new water pump? The drip is what made me change the impeller to start with, I thought the paper seal must have failed, but that doesn’t seem to be the case.

I did not run the boat at more than idle, didn’t want to get out on the lake and generate more than a drip or 2 out of the water pump.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-15-2023 at 9:27am
How's the big O ring on the impeller housing?. The spacer plate is sandwiched between that O ring on one side and the paper gasket on the other side on your vintage pump

You have 4 drain holes in the bearing housing end of the pump to give an indication of a mechanical seal leak

In the picture the screwdriver is in one of the holes


Look closely and maybe the water is dripping down from there.

If that's the case, your mechanical seal is leaking. Some people drive for quite a while with a leaky seal if the leak isn't too bad.

You can buy a seal kit to replace your leaky seal.

Not the easiest job, especially  if there's a lot of corrosion in the housing, but not too bad either

If you're dead set on a new pump, you have choices.

You can buy a new Sherwood G21 for 750 ish at SkiDim or shop around for better pricing 

You can buy a DJ pumps (South Korean company) for about 255 bucks on Ebay

link to pump on Ebay

Here's a little DJ pump discussion on CCF








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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mpost Quote  Post ReplyReply Direct Link To This Post Posted: May-15-2023 at 10:13am
If you dont have this book, download it. Lot of good info and picture of the pump assembly. Smile

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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: May-15-2023 at 11:20am
The leaking pump might also be the reason your pump would not prime.  It is getting air rather than sucking up water as it should.  You should double check all the hose connections between the pump and the water inlet at the bottom of the boat.   Any loose hose would allow air to suck in and reduce the ability to suck water as it should.   A leak between the pump and the engine would not cause any of this.   Only the inlet side affects the ability to suck water in.   
Fixing the hose leaks obviously won’t fix the leaking pump but it is a good idea to double check the inlet side hose connections at the same time you fix your pump.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tjca77 Quote  Post ReplyReply Direct Link To This Post Posted: May-15-2023 at 8:00pm
Thanks all.

KENO, yes it is leaking from one of the holes. Not a fast drip at idle but nonetheless still present. As I think back I believe I saw this a couple times last year but it was never consistent so I didn’t address it, shame on me.

I have the Sherwood raw water major parts kit, https://nautiqueparts.com/sherwood-raw-water-pump-major-repair-kit/ from Nautique Parts on the way. Just shy of 400 with the Pnd discount. I read a little on pressing the bearings and not sure that is in my wheelhouse.

I replaced all hoses a few years back, and checked the gaskets while trying to troubleshoot yesterday, all is well there.

Hated to spend the $ on the major repair kit, but also noticed some squealing from time to time that I’m thinking could be related. Should have the part here this week and will install this weekend and report back.

Thanks again for the responses and resources, it is much appreciated.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tjca77 Quote  Post ReplyReply Direct Link To This Post Posted: May-15-2023 at 8:06pm
Good info on checking all hoses on the pick up side of the pump, I will make sure that is done as well after re assembly.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-15-2023 at 8:32pm
Should be an easy job for you since the kit you linked to is all assembled and you just use the old impeller housing and associated parts and you should be good to go.Wink
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-15-2023 at 8:55pm
I can't help but notice that those thoughtful  people at nautiqueparts will  sell you the DJ raw water pump mentioned earlier in this thread to save you some money compared to buying a new Sherwood pump. 

It's in the  link

Sherwood from NP............ 749 bucks

NP's aftermarket DJ pump............ 499 bucks

Same pump on Ebay............. 255 and you can also find it for 211 dollars on Ebay  from various importers (with no name cast into the impeller housing)

You must be paying double the price for the privilege of buying it from them Wink


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Post Options Post Options   Thanks (0) Thanks(0)   Quote tjca77 Quote  Post ReplyReply Direct Link To This Post Posted: May-22-2023 at 8:09pm
Thanks all. Got the Sherwood major parts kit installed, and all is good. No more leaking and water is flowing great. All hoses are sealed and engine is running nice and cool.

I guess after 23 years of service the original bearings on the pump wore out. Keeping it as a spare in the unlikely event it is needed, it may be a weekend saver.
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