Impeller \ Water pump replacement

[The Incredible Hull]

Hi Raiders,

My motor is a 2005 40hp XR lightning Mercury (Tohatsu). The impeller has never been changed.

Decided to take a look at the impeller this morning, and it looks ok, decided not to replace it.

Why do so many people recommend changing the impeller once a year? I'm taking an educated guess, but you may change it if you've taken in other materials besides water through the pump, like sand.

2005, thats 9 years and zero cracks on the oem impeller.

[Geoff]

Other than possible damage like sand I think most people do it just as preventive maintance , it's like those who replace their trailer bearings annually.

The chances of a pump working one minuite then not the next is extremily unliky.

On mine , I keep an eye on the strength & volume of the water comming from the tell tail. If there is a good jet then I don't worry about it.

Considering E Tec don't require service for the first 3 years & even then may not be necessary to service the pump then it's fair to assume other brands would have a similar pump life.

The other aspect is how frequently the boat is used & how far you travel , ie , if going to Browns Mounton on regular trips & doing lots of hours it would be wise to service the pump more frequently than a boat only used occusionly for river fishing.

Geoff

[Fab1]

I did a impellor change on a merc that apparently went 12 years without a impellor change.

As you just found out the reason people replace the impellor yearly is because you need to remove it for proper inspection, and while It's dismantled you may as well throw a new one in as they are fairly cheap for peace off mind.

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[ray henry]

in your case your impeller has position memory.

[The Incredible Hull]

Other than possible damage like sand I think most people do it just as preventive maintance , it's like those who replace their trailer bearings annually.

The chances of a pump working one minuite then not the next is extremily unliky.

On mine , I keep an eye on the strength & volume of the water comming from the tell tail. If there is a good jet then I don't worry about it.

Considering E Tec don't require service for the first 3 years & even then may not be necessary to service the pump then it's fair to assume other brands would have a similar pump life.

The other aspect is how frequently the boat is used & how far you travel , ie , if going to Browns Mounton on regular trips & doing lots of hours it would be wise to service the pump more frequently than a boat only used occusionly for river fishing.

Geoff

Thanks Geoff, a perfect explanation.

[a boat]

Manufacturers and those who sell their products state yearly water pump changes because they make alot of money in spare parts. As you have discovered impeller can last a long time, we have had impellers that have never been serviced for over 10 years and they still pump water. That said I agree with what Fab1 said and if you go to the trouble to remove gearbox and water pump, it is wise to replace the impeller and not re-use the old one.

[Fab1]

Manufacturers and those who sell their products state yearly water pump changes because they make alot of money in spare parts. As you have discovered impeller can last a long time, we have had impellers that have never been serviced for over 10 years and they still pump water. That said I agree with what Fab1 said and if you go to the trouble to remove gearbox and water pump, it is wise to replace the impeller and not re-use the old one.

Totally agree, preventative maintenance is better than cure.

It, s like the automotive industry recommending you do a timing belt including the tensioner, idler pulleys and waterpump and not just the belt.

Best case scenario if you have a waterpump failure, or bearing failure on a idler pulley you will be doing the whole job again and replacing those components anyway.

Worse case on a interference engine-bent valves, cracked valve guides, cracked piston or all three.

When this happens you'll really know what an expensive excercise it has become.

This briggs @ stratton 3.5hp lawnmower engine has become a pile of parts due to the owner not keeping up with maintenance.

Result-scored piston, bore, crank journal, bearings.

All because of preventive maintenance.

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[Guest Aussie007]

TIH did u bend the finds back in the opposite direction to look for creases or cracks? i just showed a good mate how to change his water pump impeller on a yamaha, once it was removed we were lucky we did change it as the old impeller had marks on the fins where if left the fins would have folded in and over heated the engine costing big $$$ in a seized engine if going at a fast speed and more money to dismantle the engine to pull out the left over impeller bits

once we were finished they commented on how well it was pumping water, for a $50 part just replace it

[The Incredible Hull]

Hey Gaz,

Yer I did bend the fins back and forth, it seemed fine, almost like it was new cause it still had the little hairs on the sides of each fin.

I did purchase an aftermarket impeller and compared them both when I had the old impeller out... one of the main reasons why I didn't replace it, is the after market one looked flimsy compared to the oem one currently inside. The new impeller was overall much thinner, almost half the thickness! I reckon if I had replaced it with that I'd probably get 1 year out of it before I need to replace it again.

I might wait for another year, buy a proper oem one and replace it then. As Geoff mentions above, I really can't see the impeller working one day and completely failing the next, especially when I have inspected it myself. I'm always keep my eye out the tell tail.

Cheers for the feedback =)

[The Incredible Hull]

Oh and for those of you who want to change your impeller, do a little research on how to remove your gear linkage. I had a rough time on mine... it wasn't your usual unscrew 2 nuts and it un-links... no no no..... it was a tiny pin that is wedge in a tiny hole, and extremely hard to get out!!!

If you ever come across this situation, you can try what I did, which is to get a small philips head screw driver that is the same size as the pin, and use a hammer to firmly punch it out.

[Fab1]

Oh and for those of you who want to change your impeller, do a little research on how to remove your gear linkage. I had a rough time on mine... it wasn't your usual unscrew 2 nuts and it un-links... no no no..... it was a tiny pin that is wedge in a tiny hole, and extremely hard to get out!!!

If you ever come across this situation, you can try what I did, which is to get a small philips head screw driver that is the same size as the pin, and use a hammer to firmly punch it out.

Those are roll pins, there common on all sorts of equipment including winches.

Use a hammer and drift to punch them out when removing.

When installing tap with hammer to start and drive them the rest of the way home with the drift.

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[Guest Aussie007]

Hey Gaz,

Yer I did bend the fins back and forth, it seemed fine, almost like it was new cause it still had the little hairs on the sides of each fin.

I did purchase an aftermarket impeller and compared them both when I had the old impeller out... one of the main reasons why I didn't replace it, is the after market one looked flimsy compared to the oem one currently inside. The new impeller was overall much thinner, almost half the thickness! I reckon if I had replaced it with that I'd probably get 1 year out of it before I need to replace it again.

I might wait for another year, buy a proper oem one and replace it then. As Geoff mentions above, I really can't see the impeller working one day and completely failing the next, especially when I have inspected it myself. I'm always keep my eye out the tell tail.

Cheers for the feedback =)

thats weird mate usually aftermarket parts is pretty much a copy of the original just made on a budget i think, did u by any chance get given the wrong impeller?

something to think about when your doing 5000rpm WOT that tiny little impeller is driven by a shaft connected directly to the crankshaft so that little impeller is spinning at 5000rpm as well thats a lot and if a impellers rubber goes brittle that impeller can explode

if your happy reusing your impeller go for it did u check your woodruf key too how was the condition of that?

[The Incredible Hull]

Those are roll pins, there common on all sorts of equipment including winches.

Use a hammer and drift to punch them out when removing.

When installing tap with hammer to start and drive them the rest of the way home with the drift.

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Ah Drift tool, so tha'ts what its called! Cheers Fab =)

thats weird mate usually aftermarket parts is pretty much a copy of the original just made on a budget i think, did u by any chance get given the wrong impeller?

something to think about when your doing 5000rpm WOT that tiny little impeller is driven by a shaft connected directly to the crankshaft so that little impeller is spinning at 5000rpm as well thats a lot and if a impellers rubber goes brittle that impeller can explode

if your happy reusing your impeller go for it did u check your woodruf key too how was the condition of that?

It was in perfect condition Gaz. It was definitely the correct part, the size was the same, just not as thick which I didn't really like, could tell it was not going to last. If it was exactly the same thickness I definitely would have changed it. Will definitely source an original impeller from the manufacturer.

All in all was good experience too, was a fairly easy job, with the exception of putting the leg back on, lining up the gear linkage took about 10 goes!

Edited July 21, 2014 by The Incredible Hull

[Fab1]

Here's a picture I took of examples of woodruff keys, roll pins and the drifts/punches.

1 punch is a cut down and ground old phillips head screw driver.

Make sure you don't misplace either the key or roll pin for those that are attempting this themselves for the first time.

Cheers.

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[Guest Aussie007]

Ah Drift tool, so tha'ts what its called! Cheers Fab =)

It was in perfect condition Gaz. It was definitely the correct part, the size was the same, just not as thick which I didn't really like, could tell it was not going to last. If it was exactly the same thickness I definitely would have changed it. Will definitely source an original impeller from the manufacturer.

All in all was good experience too, was a fairly easy job, with the exception of putting the leg back on, lining up the gear linkage took about 10 goes!

holding the gearbox up while lining everything up is a real pain in the ass isnt it lol but its a quick job which can save u hundreds and do your self