Impeller Greasing in Engine Water Pump ?

[h20man]

If you are going to replace.... it may be interesting to try the Globe Composite Solutions 'run dry' impeller.........

supposedly 15 minutes run dry and no problem.....

It has gotten great reviews in Boatworks and elsewhere...

I have bought them for my Yanmar with no real premium.... and luckily all is good so far... but seems like good insurance......

(Disclaimer: I am NOT associated with Globe Composite Solutions in any way other then as a customer, and I am NOT being compensated in any way for my comments... )

[Artif]

As part of the lay up procedure I used to carry out on customers boats the engine was flushed with fresh water/glycol mix and the impeller was then removed.
A new impeller was refitted at the start of the season, I would leave the old one as a spare if it was O.K.
Regularly came across impellers that were deformed if the engine was sat for a long time, and regularly came across impellers that were starting to break up.
Always refitted with a lubricant (silicone usually) just a thin smear to help on initial start up.

[S/V Antares]

yup... we all agree. Replace it if you look at it. Once a year is a good Idea. We carry 3 or 4 spares. A comforting thought. I bought seals and bearings from a bearing shop and paid next to nothing.

A little research goes a long way.....

[Wand]

Originally Posted by Don Lucas

It's paranoid. If you allow an impeller problem to burn out your engine you weren't paying attention to start with. Replacing every year etc falls into "it makes the owner feel good" actions. I don't mind if you what to do but don't start making a big deal of it being some type of requirement.

FWIW, I'm with Don on this (sorry Don ). Just because it's easy to do, doesn't mean you ought to do it - unless it gives you a warm inner glow. Fire it up and replace only if necessary.

Ditto with replacing every year - there's simply no need imo. Attentive skippers will always get plenty of warning of things going amiss and of course engines can stand running dry from cold for a little while anyway.

Then again, down here we use our boats all year round - those who must layup thru a big freeze may have different experience and views.

[s/v Jedi]

I have seen several new impellers fail within hours while old ones keep on going. So I would not replace blindly. Remove and inspect: look at shape and find cracks when bending vanes.

Also, get one of those IR thermometers and regularly measure temperature of some key spots on the engine, incl. each cylinder and injection elbow. This gives you factual input on lurking problems incl. failing impeller.

ciou!
Nick.

[sigmasailor]

Originally Posted by At sea

Ditto with replacing every year - there's simply no need imo. Attentive skippers will always get plenty of warning of things going amiss and of course engines can stand running dry from cold for a little while anyway.
:

Problem with impellors is that as you get signs of trouble the remains of the impeller may be in your exchanger or engine; better safe than sorry goes before if it aint broke....

Eric

[s/v Jedi]

Originally Posted by sigmasailor

Problem with impellors is that as you get signs of trouble the remains of the impeller may be in your exchanger or engine; better safe than sorry goes before if it aint broke....

Eric

Ehm, read my first post in this thread on page 1... no missing impeller parts problem.

cheers,
Nick.

[sigmasailor]

Originally Posted by s/v Jedi

Ehm, read my first post in this thread on page 1... no missing impeller parts problem.

cheers,
Nick.

Not yet; keep it like that and replace it before parts go missing and end up in hard (or not) to reach places.

Eric

[sailorboy1]

what makes some believe a new unproven impeller wouldn't fall apart, while an old proven one will?

[sigmasailor]

Originally Posted by Don Lucas

what makes some believe a new unproven impeller wouldn't fall apart, while an old proven one will?

Chances are that old 'proven' ones, especially those that have been stationary for some time' will fail right after start-up. I must have replaced a couple of dozen new and 'unproven' ones and never saw one fail myself. On the other hand many a time I saw (firsthand on other peoples boats) how 'nice' the proven ones fall apart; really good fun......

Eric

[moggie]

Don, If ever I am towing you out of a nasty situation, and then you tell me that your engine was over heating, and you had not changed the impeller in three years! I would be tempted to drop the tow ( I wouldn't , but I would be tempted)
Change the damn impeller !

[Artif]

I've had to pull bits of impeller (new and old, but usually old) out of engines that were only run for a few seconds, intercooler stripped, heat exchanger stripped and check pipework. Not a cheap exercise.
Also depends on usage, if you go stirring up the bottom when motoring the dirt can chew impellers very quickly.
You can wait for your high temp alarm to tell you your impeller is FUBAR if you want, personally I'd rather check it regularly.

[s/v Jedi]

Originally Posted by sigmasailor

Not yet; keep it like that and replace it before parts go missing and end up in hard (or not) to reach places.

Eric

Sigh... you better read it then instead of pushing irrelevant info. I do not get impeller debris in odd places even if I blow dozens of impellers... because I modified the raw water circuit to prevent this.

That impellers, many old ones and some new ones, fail is a fact. Replacing impellers frequently will not prevent this completely. At some point one has to make decisions between safety, amount of maintenance and ease of maintenance. Also, experience will steer you towards better systems and better maintenance schedules.

Another tip: route the raw water hose from inlet strainer to pump so that it approaches the pump from above, even if it connects to the bottom side of the pump. This simple thing puts the pump in a low point in the circuit so that it won't have dry starts. This prevents 90% of impeller problems too without the possibility of installing a new but flawed part. Buying first grade impellers instead of the cheapest also helps.

To make sense from these wildly varying pieces of advice: if you hardly ever run the engine, you probably need to replace the impeller yearly (or remove it for the months that the boat isn't used!). If you lack the knowledge or will to inspect the impeller properly, you better replace it yearly. When you run the engine regularly and inspect the impeller regularly, there is no reason why an impeller wouldn't last two or even three years. Also, if there is partial failure after a passed inspection, you will still have sufficient cooling to pass the reefs. A quick pointing to the injection elbow with the IR thermometer (5 second job) will show you exactly what the condition of the impeller is. With some experience, you can even tell how many blades are missing from that temperature reading.
In the end, what matters is how often you experience mpeller failure. When another approach of this problem results in less failures, ignoring that alternative approach equals to SM

For some, who hate taking heat exchangers apart, a strainer that catches any impeller parts makes sense. Mine catches way more than that, like crabs, fishing line and hooks that I used to find in the heat exchanger before I added this extra strainer.

cheers,
Nick.

[dandrews]

Originally Posted by moggie

Don, If ever I am towing you out of a nasty situation, and then you tell me that your engine was over heating, and you had not changed the impeller in three years! I would be tempted to drop the tow ( I wouldn't , but I would be tempted)
Change the damn impeller !

LOL

Now that is cold...real cold.

[moggie]

No Dan, when your impeller fails, it get's HOT real HOT. LOL