When to change Impeller(water pump)

[bassfighter]

How many of you change your boat Impeller or water pump for maintenance reason?

 

I have not change mine for 10 years on an older 1979 85 hp evinrude, and still working.

 

Do I need to worry about it? It ain't broken do I need to fix it?

 

Thanks for info

[Spiel]

....I've changed a couple. In both instances I was doing lower end maintanence and decided to inspect the impeller while I had them all apart, and in both cases the impeller was cracked and showing signs of imminent failure. I'm not sure how old the impellers were or what is the expected life span but if you're working on the lower unit I'd take the time to change it. If not and it's been working fine then by all means leave her in.

[tipupesox]

After ten years of use I would change it. The impellor has a tendency to get brittle over time. All you need is a fin to break off and get clogged in the water intake. Your could fry your engine from over heating.

 

Tom

[irishfield]

Merc manuals say 300 hrs or 3 years now. That said...I have never changed an impellor..including the 1976 9.9 at the lake that still pees just fine and saw serious use as a rental motor before I owned it..and looking at it I know it was never serviced.

[Tybo]

When ever you start too worry over it.

[boatman]

The official answer ranges by manufacturer and marine tech, but 5 years is generally considered the maximum acceptable time frame. Anything longer is asking for trouble. The impeller is part of your routine maintenance and should be serviced. I would replace yours before next season. $30 and an hour of your time is cheap insurance considering the cost to replace your motor.

[lew]

It's funny, but in all the years myself, friends and family have owned outboards, which is at least 50 years that I can personally remember, I don't recall ever hearing anybody talk about changing impellers, and I can definetely say that NOBODY has ever had one fail on them, and some of these motors were ancient.

 

It's only the last few years that I've been on this board, that I've even heard mention of it.

 

My bud has a 9.9 Evinrude that's gotta be pushing 30 years old and it still purrs like a kitten, runs all the time, and still has the original impeller. Infact, I honestly don't think he's even changed the lower unit oil.

 

Not saying that's a good thing, but it almost seems like the newer units aren't made nearly as strong or dependable as the older models, as today, we hear constantly about somebodies impeller breaking down after only a couple short years.

 

Maybe our throw-away society now includes outboards too

[Uncle Buck]

I changed my cousin's impellor on his 96, 40HP evinrude this year, it was the frist time it ever came apart, we had to cut the paint when removing the lower unit...

 

i'll say one thing though... a johnnyrude impellor is much better/stronger/bigger then a merc one...

[lookinforwalleye]

I changed my cousin's impellor on his 96, 40HP evinrude this year, it was the frist time it ever came apart, we had to cut the paint when removing the lower unit...

 

i'll say one thing though... a johnnyrude impellor is much better/stronger/bigger then a merc one...

 

Hi Buck,

 

I assume the rude is working okay?

 

I had to replace the impellor on my Yammy this spring and it was new the previous fall I don`t know what happened but I was getting it ready this spring and it was working fine and then it just stopped working, perhaps the winter did something or perhaps when the dealer told me he was going to change the impellor he didn`t.

[Whopper]

I have went through two (failed) in my I/O in twelve years so I carry a spare. Mine is really easy to change more so that an outboard.

[Fisherman]

I'm sure part of the reason some may fail is due to some other circumstances maybe, like leaving the motor outside with maybe a wee bit of water left in the housing, turning the motor over without having the lower unit fully submerged, etc. Like a couple others said about old motors still running on original impellors, my sons got an ancient 1956/7 Johnson 3 HP, still shoot water out by the exhaust. I turn my Honda 25 motor over by hand about once a month, just a 1/4 turn, it's stored in a garage that's just above freezing, who knows, maybe it helps.

Edited November 7, 2007 by Fisherman

[boatman]

Impellers wear out all the time. They have since they started using rubber ones back in the 1940's or so. Some Johnson/Evinrude impellers have been in use since the 1950's. Even my old shop manuals from the 50's say to replace them occassionally. Impellers fail whether the motor is old or new. Its just good luck if they don't after several years. The rubber becomes brittle and breaks, which clogs passages and causes overheating. I think the reason people didn't hear about it as much in the past is because the world was smaller before the internet. Now we have access to millions of people and their stories.

 

There is something to what Fisherman says, though. An impeller that sits for long periods of inactivity is more likely to fail than one that is frequently used. Since the impeller is offset in its housing some of its fins sit fully extended while others are compressed. When the impeller sits for long periods it tends to dry out become hard and hold its shape. When you start the motor up it spins the hardened blades and the ones that are fully extended break or crack when they reach the compession area of the housing while the compressed fins don't expand. The impeller blades may not break off, but this condition results in a lack of cooling water being pushed up to the powerhead and causes overheating.

[OhioFisherman]

1986 35hp merc, had it changed about 8 years ago because I was getting some water in my lower unit, dude had it off anyway so I had it replaced, over due but working fine. I don`t use muffs to test the motor, I just don`t trust them, I stick my motor in a plastic barrel with water flowing in constantly. Only takes a short time of running dry to screw up an impeller.

[Tacklebuster]

I had to change mine a few years ago. When I took it out it clearly was worn and brittle and wouldn't retain its shape. I don't know how many hours the motor had since I bought it used, however I had it for 3 years and in that time I did a lot of fishing. I believe if you fish mostly in shallow water, whereby silt and weeds get into the intake then your impeller is going to wear out faster. Its not a big deal to change it yourself, so if your concerned then do it before you have bigger problems.

[bassfighter]

Thanks for all of your feedback. My unit is working fine, but just concern about it failing.

 

I will change it soon, I guess.

[musky66]

I asked my marine mechanic and he quoted me a cost of about $30 for just an impeller or $150 or so if the housing was worn as well.

How hard is it to change it out oneself? Not even sure where it is located on my 115 Yamy 4 stroke,

[Fisherman]

It's not so much that it's hard to do, but time consuming for the first time around. Most if not all, have the impellor located in the lower unit, just above the prop. On the ones I have done for friends, the shift linkage has to be disconnected, (some in the upper engine area right by the shift linkage, some in the "leg" of the shaft, [small plate covers the screw], it varies by mfgr). Then there's usually 3-5 bolts that keep the lower unit attached to the leg, remove those and gently pull down the lower unit. The impellor will be found under the cover where the driveshaft goes into the lower unit(from the top). If the lower unit is being a bit pizzy and stuck, it may be that the splined end of the driveshaft is stuck in the motor end due to exhaust carbon/corrosion. Once you open up the impellor housing, pay attention to which way the impellor comes out, some have little slots/flat spots. Probably one of the more important things when putting it back together, make sure you line up the pipe on top of the impellor output to the motor. If you don't, the water won't go to the cooling jackets on the cylinder/head. Maybe get the manual from a marine shop or find an exploded view on the net somewhere. Good luck.

[boatman]

Ditto to what Fisherman said. Buy the factory manual for your motor and get started. Also, add a little grease to the splines of the driveshaft. Replace any o-rings and seals that may be in there as well.

[Rizzo]

My unit is working fine, but just concern about it failing.

 

first of all, that's way too much information. Secondly, this should be in the thread "you know you're getting old when"

[bassmastermike]

Once every season