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barefootdiver2000

Is there such a thing as a metal impeller? Rubber ones are junk.

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barefootdiver2000

I have a 1995 Echelon in which I just changed the impeller - for the 3rd time since I've owned it. There were only 2 splines out of 8 left on it. Aftwards it was still overheating and ended up taking the scoop grate off it and pulling several large chunks of rubber out of it that was blocking water from getting to the impeller.

Seems ridiculous to have a piece of rubber that spins and falls apart every year or two. Does anyone sell a metal impeller or even hard plastic would be better than rubber.

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Bill_AirJunky

Never heard of one. So your loosing 6 blades on a stock impeller in 1 yr?

Just a guess, but there is something else wrong. I've never heard of anyone loosing them that badly

I've lost a couple of Johnson impellers over the years. And have been using the Globes the last 4 yrs. Put close to 200 hrs on one Globe & didn't lose any fins at all.

Edited by Bill_AirJunky

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jcochrane007

I don't see how anything non-flexible would work. On my boat at least the inside of the impeller housing isn't round, it's flattened on one side. I believe this is what causes it to develop the suction needed to draw water up the intake line.

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barefootdiver2000

Here's a pic of what my impeller looked like. Other two I've replaced have looked pretty similar. The junk on the left is what I pulled out of the scoop grate. The stuff on the right was in the hose on the other side of the pump, so what little water did get to the pump was getting limited by this. http://s1207.photobucket.com/albums/bb472/barefootdiver2000/?action=view&current=impeller.jpg

Hadn't heard of the Globes, but checked them out and they look like they are more durable than rubber.

I was using Mercruiser part # 47-59362T.

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mikeg

I replace mine annually. Peace of mind - inexpensive (in the scheme of things) - I consider this to be a wear item. I hate breaking down when I am on "vacation" and every boating trip is vacation for me! JMHO

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Bill_AirJunky

Wow, that pic is crazy. How many hours on that impeller? Only in fresh water? I would have said that was after at least 500+ hrs. Or maybe after sucking up something, ie; sticks, sand, gravel, etc.

BTW, there is a metal impeller inside the engine's water pump. I don't know how well it generates suction or why it's used in that pump & the rubber one in the raw water intake.

This forum has a group buy every year for the Globe impellers. I think their around $50 shipped. D-Goose sets it up. I have been replacing them every other year (about 75 or 80 hrs per yr x 2 = 150 or 160 hrs per impeller life) & then keeping the old one as a backup. Never had one fail.

Edited by Bill_AirJunky

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MLA

If your impeller housing is a composite one (common on older Merc's), then its probably grooved/scored and out of round and needs to be replaced. This will shorten the life of the impeller(s). If its metal, then inspect it for blueing and scoring. If its blue, that's a sign that it has gotten hot. May need to replace it.

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Happy to ride

Do you ever turn the motor over without water going to the engine? These type of impellers need water to cool them and it only takes "seconds" for them to heat up and come apart. I have over three hunderd hours on mine and so far no wear and still soft. If you run on water that has alot of silt in it they wont last long.

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jkendallmsce

I have a 1995 Echelon in which I just changed the impeller - for the 3rd time since I've owned it. There were only 2 splines out of 8 left on it. Aftwards it was still overheating and ended up taking the scoop grate off it and pulling several large chunks of rubber out of it that was blocking water from getting to the impeller.

Seems ridiculous to have a piece of rubber that spins and falls apart every year or two. Does anyone sell a metal impeller or even hard plastic would be better than rubber.

Do you run the engine outta the water?? ever?? it only takes a few seconds to destroy an impellor, as the water both cools and lubricates. I just changed mine, and the local shop says the Inmdar manual, in a real non logical way, says to change every year, or every 50 hours. Actually showed me in the Indmar manual.

And the same shop said impellors are not the same quality they were years ago.

Pretty cheap preventative maint, when compared to how much a new engine costs, or if a chunk of impellor makes it into the engine and gets stuck.

Edited by jkendallmsce

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cowwboy

In theory you could go to a sliding vane pump. But would not be cost efective and would be all custom internals so parts would be insane.

I have wondered why they don't use them as they use the same princiaple as a flex impellar.

They were even used in old school superchargers and massively used in vacuum pumps today.

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jkendallmsce

In theory you could go to a sliding vane pump. But would not be cost efective and would be all custom internals so parts would be insane.

I have wondered why they don't use them as they use the same princiaple as a flex impellar.

They were even used in old school superchargers and massively used in vacuum pumps today.

your sliding vane pump would require waaay more precision and would be way more expensive than the exisiting impellor that you can buy for about $30.

And the sliding vane pump would not pull enough suction/vacuum when idling.

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BuFootin

Never heard of one. So your loosing 6 blades on a stock impeller in 1 yr?

Just a guess, but there is something else wrong. I've never heard of anyone loosing them that badly

I've lost a couple of Johnson impellers over the years. And have been using the Globes the last 4 yrs. Put close to 200 hrs on one Globe & didn't lose any fins at all.

Agree with Bill. You have something else going on that is destroying your impellers prematurely. Does you raw water pump get warm when you first start the boat? If the pump does not prime, it will run dry and the rubber will heat up and tear up the vanes. Also make sure the gasket on the pump coverplate is in good shape. If in doubt replace it. That will insure you have a good seal on the pump and not drawing air in, causing the pump not to prime.

let us know what you fine

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NorCaliBu
I have a 1995 Echelon in which I just changed the impeller - for the 3rd time since I've owned it...

Your boat is 17 years old. I have a 2000 that I've owned since 02 and I've changed the impeller 10 times. Never had one come apart but I change it every year.

Edited by NorCaliBu

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Lance B. Johnson

Like everyone else says...

Don't run it dry. Change the impeller housing.

I just changed mine today after two years of service. It looks absolutely perfect.

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martinarcher

My boat is 25 years old and is probably on it's 3rd or 4th impeller. I change it every 100 hours and it has never been missing a vane. I'm guessing your impeller housing is messed up and chewing up impellers. I've never heard of a boat eating them up like yours is. I would change the housing if it were my boat.

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GreenMan

Wow, that pic is crazy. How many hours on that impeller? Only in fresh water? I would have said that was after at least 500+ hrs. Or maybe after sucking up something, ie; sticks, sand, gravel, etc.

BTW, there is a metal impeller inside the engine's water pump. I don't know how well it generates suction or why it's used in that pump & the rubber one in the raw water intake.

This forum has a group buy every year for the Globe impellers. I think their around $50 shipped. D-Goose sets it up. I have been replacing them every other year (about 75 or 80 hrs per yr x 2 = 150 or 160 hrs per impeller life) & then keeping the old one as a backup. Never had one fail.

The raw water pump is a 'positive displacement' style of pump in order to assure reliable priming and water delivery to the engine, particulrly where the pump sits above the mean water line.

The on-engine circulating pump is a centrifugul pump that doesn't require priming because in the normal automotive application it is constantly flooded as it effectively is in our boats because the raw water pump delivers feed water to the engine pump.

Oh yeah, like others have said, DON'T EVER RUN IT DRY!

Edited by GreenMan

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cowwboy

your sliding vane pump would require waaay more precision and would be way more expensive than the exisiting impellor that you can buy for about $30.

And the sliding vane pump would not pull enough suction/vacuum when idling.

Never said it would be cheap. Just said it's a possible change.

You could use the existing housing just machine your hub and spec out your vanes.

If it's below water line massive suction isn't required. But why do you think at 1k +/- rpm would not pull suction?

These pumps are used mainly for vacuum pumps and you can change the pulley to whatever size you need.

Jabsco offers sliding vane pumps in the same line as the flex impellar but the main difference is cost.

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Wakesetter67

I had the same type of pump on my old boat. 13 years and 850 Hr never had a impeller issue, I changed it every year, as part of my summarizing routine. I'm sure there are cases of sucking up something and causing damage, But I think in general you should not have a problem if you follow this routine..

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Nitrousbird

Why not just buy a Globe 100J Run-Dry and be done with it?

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NorCaliBu
Why not just buy a Globe 100J Run-Dry and be done with it?

:unsure: You do know that Globe impellers don't last forever, right? :unsure:

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Lance B. Johnson

In theory you could go to a sliding vane pump. But would not be cost efective and would be all custom internals so parts would be insane.

I have wondered why they don't use them as they use the same princiaple as a flex impellar.

They were even used in old school superchargers and massively used in vacuum pumps today.

Honestly I am not fond of that idea....it rules out the possibility of fixing any problems while on the water. Many of us carry spare impellers.....at least I think so right????

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Lance B. Johnson

Why not just buy a Globe 100J Run-Dry and be done with it?

People that buy globes buy them so they can run them dry, not so they don't have to change them. Interestingly most change them out just as often as the johnsons.

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jkendallmsce

Never said it would be cheap. Just said it's a possible change.

You could use the existing housing just machine your hub and spec out your vanes.

If it's below water line massive suction isn't required. But why do you think at 1k +/- rpm would not pull suction?

These pumps are used mainly for vacuum pumps and you can change the pulley to whatever size you need.

Jabsco offers sliding vane pumps in the same line as the flex impellar but the main difference is cost.

Why spend much more, when the existing system has worked on thousands of boats for many decades...not practical nor logical.

And the impellor/pump is not below the water line...unless the boat is sinking...so suction/vacuum is critical to the operation of the boat and keeping the engine running cool. You can caluculate using NPSH (net positive suction head) calcs if you'd like to confirm.

ANd if you look at how the system works, when running, the intake beneath the boat is a scoop that directs/forces the water into the hose and ultimately into the pump...when idling, that does not happen. SO when idling, vacuum is the only way water gets to the pump...That is why the hose from that scoop to the impellor pump is reinforced with wire...so the hose does not collapse when under a state of vacuum. You notice that other hoses on the boat are not reinforced with wire, cause they do not experience suction/vacuum conditions.

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barefootdiver2000

Thanks for all the replies. Think I'll order a Globe for backup and use the next time I change it out. The housing is a little out of round, but I thought that was the way they were designed? Didn't see any scoring or grooves inside of it and I don't run it dry

I took the boat out this weekend and the new impeller is working. But the temp does seem to creep up when the boat is running idle but not in gear.

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