Outboard water impeller, how often to change?

woodster · Jan 24, 2015

Bad Obsession said:
How often do you replace your outboard water pump impeller?

How often do you re lubricate your lower unit?

I have heard of some people saying 1 time a year and others saying 1 time every 3 years. I really didn't run my outboard for that many hours last year and the P/O said that it has recently been done. Debating on changing mine this spring.

watch the pee hole and if you are getting a good steady strong stream just use it as for the lower unit change it now then you will have a reference to go by going forward

woodster · Jan 24, 2015

Bad Obsession said:
I get a good steady stream. Except for this one morning at the end of my last cruise. I had to stick a wire up in the pee hole because it stopped spitting water. That worked and it ran like a top the whole way home (3 hours).

Just wondering if I should change it or wait on it for this season. It ran like a scalded dog last year and it started easy too. Good old outboard.

they will clog up some times because the screen on the foot is not that fine tuned and things do get in the system you did the right thing by sticking a wire in the pee hole ..had you not been able to clear it out then you may have had problem and also insects some time get in the pee hole as well just always check the pee hole when cranking it up that is sorta like the water temp alarm on the bigger engines (inboards)

Ron20324 · Jan 24, 2015

"mud daubers" make home in that hose. I had it happen, then after that kept something stuck in the end when the motor was not expected to be used.

finding41 · Jan 24, 2015

I change my impellers yearly on the charter boats. And every 2 years on the boat I use. (I keep the old ones on the boat as a back up just in case.)
Just note that the impeller tends to keep its shape when it sits in the pump housing. It is off set to one side and the flaps on the offset side are curved more than the other side.
If you pick up a used motor always change the impeller first thing.

Picflight · Jan 24, 2015

Definitely change the impeller when you get a used outboard, this would your maintenance reference going forward. It also gives you an inspection reason and cleaning of an mud in the housing.

seadaddler · Jan 25, 2015

pee hole

My pee hole does get clogged every so often and I keep
a piece of wire handy to clean it out and if like mine the flow
shoots out very good so I just try to flush with fresh water often.
But my outboard is for my dink and if I had a outboard for my big boat
I would check things more often and in winter would check the impeller
and lower unit lub every other year or every year.
I got my outboard used and the PO had it serviced complete every year
but I just been taking the carb off and clean all the jets when it starts running different and it is a 2 stroke and add plenty of seafoam.
Nick

svchickadee · Jan 25, 2015

Changing the lower unit gear lub shows if water is getting into the unit. I change my yearly.

Charlie Jones s/v Tehani · Jan 25, 2015

A good stream out of the pee hole is not always a reliable indication. I had a quite good stream, but when I disassembled the lower unit, this is what the impeller looked like. Luckily all the pieces were in the housing.

I'm beginning to maintain a hour log, and will change after a year first time, then decide.

watercolors II · Jan 25, 2015

Lower unit oil change every fall

As already stated I watch the pee hole when running. I agree also with “svchickadee” changing the gear lub especially if you store your unit in a freezing climate.

This past fall when I pulled my boat for the winter, it sat in my driveway for over a month till I was able to service it for winter storage. Because it sat for over a month the water and the grease in the lower unit separated and the water was on the very bottom of the gear chamber, so when I opened the drain about one half cup of clear water came out before the oil started to flow.

Joe Blizzard · Jan 25, 2015

Bad Obsession said:
How often do you replace your outboard water pump impeller?

Mine was two years old and had about 15 hours of run time when I decided I'd go ahead and change it as a precaution this winter. When I got it out I found one of the vanes split and ready to separate.

thinwater · Jan 25, 2015

IF the pee hole clogs, LOOK at the bits that come out. If they are black (impeller bits) change it right now. They are going to get caught other places in the engine and you will have spot overheating.

rgranger · Jan 25, 2015

I change my lower unit oil at the end of each season. My thinking is that if any water got in, I don't want it sitting in there all winter doing what water does. I also agree on the idea of changing an impeller on any used outboard you buy. Then you have an idea of how old it is... and you also know how much you use your O.B. (If I was a real sailor, I'd keep a log of engine hours)

finding41 · Jan 25, 2015

A few people have mentioned hour logs.
Is there a small automatic hour log that can be attached to an OB?
That would be very handy for me.
I don't mean to hijack the thread. But I think this would be very helpful with maintenance scheduling.

Chris & Lenore · Jan 26, 2015

It depends on what goes through it. I change mine at three years but check if annually (only takes 10 min). I have never seen any wear or cracks when I flex the blades.

One thing I remember a mechanic saying - OEM costs a little more but lasts longer, especially from cracking. I always buy OEM.

Chris

Leroy McMillan · Jan 26, 2015

I was a service manager at a top 25 Yamaha dealership in the U.S..I attended Yamaha university. Here is the deal as I expierenced it. All impellers should be changed at a minimum of three years. Some will not make it that long depending on many things, how often it is used...too little and it will deform and tend to dry rot. Use it alot and it will wear out from spinning around in it's housing. Temperature in your area has some to do with it also.Hot is bad. Yamaha keeps good records on Service throughout the U.S.. They say that places with High, gritty sediments go through Impellers faster than clear water. Mobile Bay Alabama is the #1 harshest Body of water on impellers. They say they really do not want to sell Jet drive motors in that area due to sand and grit wearing out the drives. I have also found that the OMC, Evinrude/Johnson impellers last twice as long as any others for some reason. I have seen them good at seven years. Here is the bottom line.... If it were my motor I would do it every year if it was used in saltwater for one simple reason....The lower unit bolts will cease up if not broken loose on a semi regular basis. Freshwater can go up to three years. I would not tell anyone to go any longer than this.If you live in a sandy/high sediment area it is going to be more worn than in clear clean water. Use your judgement about what kind of boating you do...How far will you be from help if it goes out etc.I will give one more piece of advice. If you are running a outboard with a freash water rinse down garden hose hook up and happen to have a raw water wash down pump.....it can be hooked up the the motor at the fresh water rinse attachment , turned on and run. It will force water through the motor to keep it cool. Get the boat on plane and back the motor off just enough to keep it on a plane an get straight home. You will not find this in any Yamaha book as it could lead to liability if a motor was damaged due to overheating but if you need to get home and no one is around to help......well you decide.

Capt Thomas · Jan 27, 2015

Replace water pump impeller every year, no matter how many hours. It is cheap insurance and assures that all fasteners are properly anti-seized.

Brian S · Jan 27, 2015

Hey, Finding41… there are battery operated tachometers that can provide hour meters.

I have this one: http://www.amazon.com/Tachometer-Kawasaki-Motorcycle-Generator-Snowmobile/dp/B0049IFX56

It has just 1 wire, which wraps around the spark plug wire, and using induction, counts spark plug firing pulses.

I have used it a few times, just to check RPM at idle load and WOT, with stock prop and high thrust prop. I don't use it for hour meter. I'm not sure where one would put it for that purpose, what with rain and such.

MrBill_FLL · Jan 28, 2015

I do it annually. (or did). the impeller was tiny. and I run in salt.

2 things I do (and suggest), when you know the impeller is good, put your hand in the pee stream and gauge the temp. (on mine it would be warm, not hot). - I could hold my hand there forever... your might be 5 seconds.. baseline it the key.

2nd thing is pull the cover and place a finger on the head. then count 1 Mississippi, 2 Mississippi, etc.

When you need to pull your hand away you have your base line.

often a leg will break off the impeller. (and that part might migrate to the head -ohNooooo! )

it will still pee, but the temps are up.

You won't know its broken, unless you have a head temp gauge, or do the Back Yard Engineer tests.

the other thing I'll do if the boat has been sitting on the hard for some time, is soak the impeller (entire lower unit) in a bucket. that will help the rubber swell and might not break off a leg or stick to the sides.

+ if you're not pulling the prop, how do you know when you pick up fishing line between the prop and seals... fishing line can chew up the shaft seal...

LU oil once a year, and I might check it before a long trip (no milk colors.)

my .02

Outboard water impeller, how often to change?

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