Raw Water Impeller Change

[KevinMc]

When I replace the impeller for the Sherwood raw water pump I get a constant trickle of water coming out of the pump once I remove the casing with the impeller inside from the base. (And yes, I close the seacock before I start.)

I know the seacock is not leaking since I've cleaned the sea strainer before and no geyser has appeared when I've opened the sea strainer to remove the basket.

By the time I've completed the impeller change (15-20 minutes) with water trickling out the entire time I have about 1.5 gallons of water to remove from under the engine. I can understand a certain amount of water in the hoses would flow out but 1.5 gals seems like a lot of water.

Any ideas?

[MorningStar]

Check your vacuum break for the engine. There are two. Maybe they are not releasing water when the engine is shut down.

Barry
s/v Morning Star #35
Kemah, Texas

[Carolina.Mind]

The leak is from the vent hose for the shaft seal. You just need to clamp the hose (e.g., vice grips) to stop the leak.

[russp]

Hi Carolina.Mind, Oddly enough my Sherwood pump seal has started leaking just as this topic was being discussed on the forum. Could you please explain where the vent hose for shaft seal is that you mentioned, I don't recognise this at all?

Regards

[leigh weiss]

Russ,
The factory sent a retrofit kit to owners several years ago to provide venting of the shaft seal and positive water flow to the shaft seal.
This kit has a vented loop located on the bulkhead above the forward engine hatch. I have found that this vent should be cleaned and lubricated with silicone spray to keep it from sticking closed. This is the same type of vent that is in the shower sump drain line. My shower sump vent stuck closed and this caused a back siphon filling the shower sump and drained into the bilge if the sump pump switch is off. If the switch is "ON" the pump will cycle. Woke up to wet head floor and bilge pump running!!!!!
Check to see if you have this type of shaft seal venting. If you have to squeeze off the hose to prevent back flow, then this vent is not working!!!!
Cheers

Leigh