Sherwood impeller

[Fou Du Large]

Hello!

I would like to know how long do you run with a new impeller?

With my Sherwood pump (old model) I run my M-25 for about 70 hours...
I need to change it every spring before sailing season.
I run in soft water no mud or anything like this.

I dont see anything wrong in the pump.
I looked to the intake,  the marelon valve ½ is not ½ hole just about 3/8''??? I think there is a restriction of the water flow, and plan to change this valve next season...

Anyway this is not normal to run 70 hours with a impeller.....

In my C&C-29 i didn't change this impeller in 6 years????

Your input please?

[Ron Hill]

Fou : What you need to do is inspect the impeller annually.  Pull it out of the pump and bend the blades looking for cracking of the blade where they join the hub.  If no visible cracking spray the impeller with silicone, let it dry and if the boat is hauled wait to reinstall it in the spring - otherwise reinstall it.

I keep all of my spare impellers in a Zip lock bag sprayed with silicone(to keep them nimble).

You might get a number of years out of an impeller, but you must inspect it to make sure there or no cracks. Every blade that I've seen come off of an impeller started with a crack at the hub.  A thought

[Fou Du Large]

That is what i do.
I inspect the imp. every year and it is always craked and broken
I always need to install a new one every year sometime two...
I'll try silicone and remove it for the winter...

Thank you!

[David Arnold]

Is the impeller's worst enemy salt?  I put a "Y" valve right by the raw water intake and when I leave the boat for the weekend I turn the valve and flush with fresh water.  Instead of leaving the boat with salt water from the intake to heat exchanger and muffler, there is fresh water throughout including the impeller.  This system also makes it a breeze to run anti-freeze through the system when it's time to winterize.

[Ted Pounds]

FWIW I read somewhere that the impeller's worst enemy is the pink anti-freeze.  So I always removed mine after winterizing and cleaned it off.  Then re-installed in the spring.  They usually lasted 3 years that way.  And even then they seemed OK, but I would replace them anyway and save the old for a spare.

[Ron Hill]

David : I'm not too sure that salt water really "attacks" the rubber in the impeller.  That type material holds up fairly well, but the metal "C" clip, brass run plate and other components of a Sherwood may NOT!!

However, your idea of a "fresh water rinse" thur the impeller is a GREAT idea. I immediately think of the HX zinc, the end cap gaskets and other exhaust components not having to sit in saltwater - till you start the engine again (days/weeks away!).....is an ingenious idea!! 

I'm going to try that.  Thanks ! 

[Roc]

I take my impeller out every winter, otherwise the fins will take a 'set' and will stick to the pump body.  Upon first start-up, that can break a fin.  I submerge the impeller in a non-petroleum lubricant, like cooking oil.  I end up using the same one for at least three years, but in reality, they looked perfectly fine after that time.  I end up swapping them out for new ones after about three seasons just for the sake of getting a new one, but they still looked just like new.  Submerging them in cooking oil was suggested at a local diesel seminar I took several years ago (Mack Boring, Yanmar distributers)

[Ron Hill]

Roc : We've had this discussion before, you prefer virgin olive oil and I prefer silicone. 
I've always taken my impeller out of the pump and taken off the drive belt as it makes no sense to keep the drive belt tensioned or the impeller squinched up during winter lay up. 

[Ted Pounds]

I always used Vaseline...