How to ID bad impeller

JK_Boston_Catalina310 · Feb 19, 2014

c130king said:
Did a search but found nothing...not having much luck with search. Have had my 310 for 18 months and put over 300 hours on the motor. Today I figured I would change out my raw water pump impeller...just sort of assumed it might need changed. No issues with it. But it looked fine to me. No tears, still flexible, no brittleness. In other words saw no issues. So I put it back in and all continues to work fine. How long do impellers usually last? Do you just leave it there until the raw water stops working? How would I know it needed to be replaced? Thanks, Jim

I replace mine annually. I keep the old one as a spare for that year. Then repeat again each spring. This is based on advice from Maine Sail.

The cost is small in terms of the high potential costs of running your engine hot. And with the pain of changing on the stock pump on the 310 I would never put an old impeller back in. I also changed pumps to remove that problem.

woodster · Feb 20, 2014

changing annually is a good way to also be able to check out the impeller shaft and bearing while doing it ...along with your drive belt as well.....

regards

woody

JK_Boston_Catalina310 · Feb 20, 2014

c130king said:
Thanks. I do have spare...but I don't think it is brand new. I will go find a new one and install. It was not really that difficult to get the Sherwood pump removed. The bolt heads are on the back side. But it only took about 15 minutes to get the pump removed, hoses off, impeller out and then put it all back together.

I presume if I take the old one to my marine parts store (not WM) they can match me up a new one.

Cheers,
Jim

Here is the part number and info on the impeller and gasket kit. http://shop.toadmarinesupply.com/ma.../index.php?p=details&mfc=Universal&sku=200175

I got mine from my local Westerbeke guy before I changed pumps.

The problem I had is that 15 minutes at the dock can easily turn into 30 minutes or more when you have an engine problem in a busy channel and your boat is getting tossed side to side by wake and waves. Having a water pump with 4 screws on the front of a plate that can be taken off in seconds and gives direct access to the impeller without having to remove a hose makes the whole process quicker and easier. Since we planned on keeping the boat for a while I thought it was a worthwhile upgrade.

Fair winds,

Jesse

Bob James · Feb 20, 2014

JK and or others: Could you supply a link or part number/mfg/source for a replacement for the Sherwood pump. I will be changing impellers in a couple of months and may just change out the pump at the same time. Thanks!

JK_Boston_Catalina310 · Feb 20, 2014

bobjames said:
JK and or others: Could you supply a link or part number/mfg/source for a replacement for the Sherwood pump. I will be changing impellers in a couple of months and may just change out the pump at the same time. Thanks!

Here is the previous thread on the water pump change. http://forums.sbo.sailboatowners.com/showthread.php?t=139566

Please let me know if you have any specific questions.

Good luck and fair winds,

Jesse

Tom J · Feb 20, 2014

It is possible to remove the impeller cover screws from the Sherwood pump without removing the pump. You just have to be good at working backwards and blind folded, not unusual with many jobs a mechanic finds himself involved in. But like Jesse said, the pump upgrade is well worth doing, and is on my list. After my last trip up the ICW from Florida, I found the bearings were toast, and the shaft was scored on the Sherwood, so I had it rebuilt, but eventually it will be my spare.

Stu Jackson · Feb 21, 2014

Jim, in addition to Jesse's remarks, please be aware that the Sherwood pump materials are not as good as the Oberdorfer. I'll find some links for you later today that point that out, but in addition to the simplicity of the faceplate on the O compared to the S, that's why they call the Sherwood a piece of S.

Oh, try this: http://www.c34.org/wiki/index.php?title=Replacing_a_Sherwood_Water_Pump_with_an_Oberdorfer

JK_Boston_Catalina310 · Feb 21, 2014

c130king said:
Just got a quote from Depcopump for the Oberdorfer...$230.

I am thinking I will pass for now. It just wasn't that difficult to remove and it is working.

But I will go find a new impeller and add that to my annual maintenance checklist.

Cheers,
Jim

Nothing wrong with that approach. Sooner or later the Sherwood will start to weep water and it will be time to rebuild. That's when I would address it.

One of the key reasons I did the upgrade is we plan to take our 310 down the ICW to the Bahamas and the Caribbean. In doing so, I am making my systems as bullet proof as possible.

I found the easiest way to change the impeller on the Sherwood is to actually remove the pump from the engine. Undoing the two bolts that holds it to the engine was easier than messing with the bolts backwards and undoing the hoses.

Jesse

Tom J · Feb 21, 2014

c130king said:
Just got a quote from Depcopump for the Oberdorfer...$230.

I am thinking I will pass for now. It just wasn't that difficult to remove and it is working.

But I will go find a new impeller and add that to my annual maintenance checklist.

Cheers,
Jim

Not a bad price when you compare it to the cost of a new Sherwood.