Impeller Greasing in Engine Water Pump ?

[Mark Zarley]

Jedi, looks like a reconfigured bilge pump strainer to me. Not a bad idea. What about leaving the original screen in and catching smaller particles or is that to restrictive? Good visual warning system of impending failure if one would bother to look. Don Lucas, impellers get their set from months of idleness. Running the eng on a regular basis will prolong impeller life. I would not down play the importance of prevenative maintance, changing fuel filters,V-belts,coolant hoses and impellers before an "in service" failure is good responsible boating. When we have trouble on the water there is no safe Highway Berm to pull over on to wait for assistance. Preventing break downs while on the water is of the upmost importance.

[s/v Jedi]

Originally Posted by Don Lucas

Did a poll once and it isn't common to replace requarly and the number of people who have had their seawater impeller fall apart were a lot fewer than what gets talked about.

The impeller on my 4-cylinder Yanmar stays good for ever, but it's rather big (140hp engine). On my 10hp 3-cyl diesel genet, I need more than 1 new impeller per year. I replace it when it starts loosing parts, but it's still pumping close to full flow at that point so not a real big problem.

I think small impellers fail quicker.

cheers,
Nick.

[David M]

Petroleum based grease like Vaseline causes rubber to swell and weaken. Silicon grease does not have this effect.

[GordMay]

Originally Posted by Don Lucas

... Did a poll once and it isn't common to replace requarly and the number of people who have had their seawater impeller fall apart were a lot fewer than what gets talked about...

Perhaps those doing the talking (about impeller failures) didn't respond to your poll.

[US1Fountain]

Originally Posted by Mike OReilly

.....
If it's in good shape just re-insert with a little silicon grease. If it feels stiff, or worn, replace it. Impellers are cheap.

I replace mine every 2 yrs, just because they are cheap and I rather replace them on my terms, not when they went out.
BTW, if one goes to the trouble to pull apart and inspect, I'd recommend to just install a new one.

[S/V Antares]

Ziggy, Real good point. Your #2 failure mode is a real stinker. Pulling the cover off and looking at the impellor one will not see this failure. You have to take the impellor out and see if the hub is separating from the rubber. I have first hand knowledge on this! bit me in the butt.

[hugosalt]

Had #2 failure (rubber separate from metal core) between the jetties entering harbor, no wind and very big ferry closing in...
mr. independent was very happy to be a sea tow member and
make use of there services for the first time...as their tow boat was coming in directly behind me with in hailing distance!!

That impeller had been install bearly 3 months prior and had
about 40 hours on it.

Still I like to change impellers, filters early and often!

[phantomracer]

Originally Posted by Ziggy

This is a small thing that is worth worrying about. Impellers are a lot less expensive than new engines. On my Yanmar the impeller definitely needs a bit of silicone grease when starting after a layup to prime, and the new impellers come with a little packet of grease in the box for this purpose.

I replace the impeller every year.

Not anymore. the last batch of Yanmar brand impellers I bought for my 3GM30f came sans grease. Of course there could be NOS still on the shelf with the grease at some suppliers

I just use whatever I have laying around..soap..veg oil..etc to get the impeller in..every time taking it out in the fall, it looks as pristine as when I put it in.

[Ziggy]

Originally Posted by phantomracer

...every time taking it out in the fall, it looks as pristine as when I put it in.

So do mine, but see failure mode #2 in my earlier post. Mine looked pristine even after they failed.

[phantomracer]

Originally Posted by Ziggy

So do mine, but see failure mode #2 in my earlier post. Mine looked pristine even after they failed.

which is why I still replace them no matter how good they look! Unless it is an emergency...once an impeller comes out..it NEVER goes back in!

[Saltyhog]

Sometimes fixing what's not broke can cause it's own set of problems. The impeller shaft on my Westerbeke is keyed to the impeller with a Woodruff key. The first time I changed the (admittedly pristine) impeller, the key stayed in the key way when I removed the old impeller. When I inserted the new impeller, I aligned the keyways, however the key was pushed back and behind the new impeller, and then dropped down to lie across the raw water exit port. The whole thing went back together with my noticing any of this. When weeks later I started the engine, no water flow! I was lucky that the key was across the port and had not aligned with it and dropped into it which would have made a lot more work to retrieve. The thing is, the old impeller looked near new, but as the engine was new to me, I changed it as a matter of course. I'm not saying don't do PM on the engine, just that some times the best of intentions go wrong. That's when the "If it ain't broke don't fix it" folks get all smug!

[Ziggy]

Originally Posted by Saltyhog

Sometimes fixing what's not broke can cause it's own set of problems. The impeller shaft on my Westerbeke is keyed to the impeller with a Woodruff key. The first time I changed the (admittedly pristine) impeller, the key stayed in the key way when I removed the old impeller. When I inserted the new impeller, I aligned the keyways, however the key was pushed back and behind the new impeller, and then dropped down to lie across the raw water exit port. The whole thing went back together with my noticing any of this. When weeks later I started the engine, no water flow! I was lucky that the key was across the port and had not aligned with it and dropped into it which would have made a lot more work to retrieve. The thing is, the old impeller looked near new, but as the engine was new to me, I changed it as a matter of course. I'm not saying don't do PM on the engine, just that some times the best of intentions go wrong. That's when the "If it ain't broke don't fix it" folks get all smug!

Believe me, I have learned the wisdom of "if it ain't broke don't fix it" many times over. But in the case you describe, I think you're actually better off to have gone through the experience of changing the impeller and pushing out the key. It would have been a lot harder if you had to change the impeller for the first time in a busy sea lane in bouncy seas, especially if the key had fallen into the port! Now you know what to watch out for and you have reduced the likelihood of having to do it in an emergency.

[Saltyhog]

Originally Posted by Ziggy

Believe me, I have learned the wisdom of "if it ain't broke don't fix it" many times over. But in the case you describe, I think you're actually better off to have gone through the experience of changing the impeller and pushing out the key. It would have been a lot harder if you had to change the impeller for the first time in a busy sea lane in bouncy seas, especially if the key had fallen into the port! Now you know what to watch out for and you have reduced the likelihood of having to do it in an emergency.

You're absolutely right. The time to break something or create a problem is at the dock. I suppose I was just frustrated with the design of pump. Seems silly to have a key that can fall out and potentially cause a problem. A splined shaft would make much more sense. Such is the nature of boats I suppose. Our job is to know them, warts and all. Great sig line btw.

[Vyndance]

If the water pump is below the waterline and the seacock is open there is no need for grease ever. It will be flooded. A sitting in the same form for 20 years impeller will probably come unglued on the first revolution.

[Solitude]

Replace it. Its cheap peace of mind.