How do you know when your waterpump (is that Impeller?) is busted?

[WalleyePaul]

Hey all you boaters,

I've got a little or a major problem however which way you see it, please tell me. (I'm a first year proud Tracker boat owner with a 40 hp mercury outboard)

Here's the situation, I last took my boat out to Jordanelle just before winter set in. I noticed that the water wasn't coming out of my engine. You know a nice strong stream of water shooting out which is a healthy sign. I became very concerned, because apparently I had forgotten to clean the engine with suction cups with hose two or three times before jordanelle, and I saw a green agae buildup covering in the hole where the water is supposed to stream out. I took the boat home immediately.

I cleaned the hole with a long dull needle very carefully, and then applied the suction cups to my engine and turned on the water. Then I turned on the engine... there was a very nice long powerful stream of water (which of course my kids was dancing into its shower! Heh heh) I was relieved to see that it was streaming nicely.

The problem is, I was out on the lake for about half a hour before I even noticed it. Is it busted? I hear the impeller or the water pump whatever its called is very sensitive piece of rubber spiral, and it doesn't take much to ruin it. So guys how do you know if its busted without taking the engine apart?

It cost $75 bucks a hour plus parts at SS marine in Orem where I bought it from. I'm trying to save some money here, since my little son's birthday is today and I could use 75 bucks to buy him a bike.

I stablized the gas and fogged the engine for winter storage
and now I'm in the process of getting my boat ready for spring. What do you guys say?
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[longhotsummers]

I had a similar experiance shortly after I bought my first boat. I had beached my boat in the sand and must not have pulled the engine up fast enough. The sand tore apart the little impeller. I didn't know it wasn't pumping water until the engine seized. Luckily the engine wasn't permanently damaged and I repaired the water pump myself. The kit was only $25 and it took about an hour- I'm not terribly mechanically inclined, but it wasn't to tough.

I would say that if it is still pumping a good steady stream then you are probably ok. Just take a peak out the back every so often to make sure that it continues spraying.
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[crestliner]

[] Is your motor two stroke or four? My new boat has a four stroke motor and the water pump is thermostat controlled. I noticed that it would take upto five minutes before the water stream would start and became alarmed that something was wrong. The guys I bought the boat from told me with a thermostat, the colder the motor and the colder the water, the longer it will take for the stream to start. That explains why it worked fine until I started using this winter in water like Bear Lake (33 degrees) and Strawberry (just before ice up-32 degrees). I just let it idle until it warms the water enough to open the thermosat before I take off.
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[Teroy]

I learned my lesson on Pineview last year. I now replace mine every spring. Maybe a little overkill, but better safe than sorry. It doesnt take a lot of cold weather and debris to destroy a rubber impellar.
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[WalleyePaul]

Ummmm not sure if its a two stroke or four. It's a standard 40 hp mercury tracker. Im sure its a two stroke otherwise it would mention that on the engine.

So guys tell me, you think my engine is ok now that its running (not seized) and streaming good water?

I'm catching my collective breath here guys, cuz I was high speeding across from hailstone marina to the rockcliff where I begain my slow trolling and stopping at several coves for smallies, when I noticed there was no water coming out. That was probably a good 45 minutes of running the motor there, and then getting back to the marina which is another 15 minutes very slow with another fellow boater side by side in case of emergency.

Then I take it home and clean it out and suction cupped the motor with water and it works fine... think I'm just very lucky here?
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[IceFishingGod]

WalleyePaul,

Your motor is fine. I'll assume it's a newer (post 1980) outboard. Here is the way Mercury and most other engines operate. The stream you see coming out is called the thermal bypass line. This allows water pumped by the impeller to exit the engine without going thru the internal parts. There is a thermostat just like in your car in your outboard, it doesn't allow water to reach the internal parts of your motor until the engine warms to 130 degress (give or take a few depending on type). Once the engine warms to the temprature that the thermostat is set at, the thermostat opens. This directs the water thru the internal water jacket surrounding the motor. This hot water is then expelled out the bottom of the engine thru the center of the prop. This feature is know as thru hub water exhuast. To check if everything is working properly heres what you do. Put the hose and cups on the motor in your driveway, once you start the motor you'll see the water coming out the ports in the back. As the motor warms up the stream will get smaller and you'll see water starting to come out of the center of your prop. If there is no water coming out of the center of the prop, but, a small exhaust port above the skag facing aft, it does the same thing. It just means your engine doesn't have thru hub water exhaust. As you increase the RPMs in the engine the water should come out faster as the RPMs increase. This checks to make sure your impeller is not cavatateing (sucking air instead of water). I've made some assumptions here not knowing all the particulers but I think your motor is fine.

[WalleyePaul]

Oh man Thanks IFG! Now I can breath abit easier! Thank goodness the mercury folks know how to make their outboards! My outboard is a 2001 mercury. I'm thankful for the great technology!
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[RipNLips]

No [size 1]guarantee[/size], but it sounds to me like you probably lucked out. You said the hole was filled with algae. The algae was probably just keeping water from coming out of the indicator hole even though water was pumping through the rest of the system fine. If water is coming out of the indicator hole now and the engine doesn't seem like it's running poorly or heating up excessively, you're probably allright. It may not hurt to check out or replace the impeller however. It'll give you piece of mind during those long cruises if nothing else.


Although it focuses on cold weather boating, there's a good thread BLM started that should interest you. Check out [url "http://www.bigfishtackle.com/cgi-bin/gforum/gforum.cgi?post=28813;sb=post_latest_reply;so=ASC;forum_view=forum_view_collapsed;;page=unread#unread"]this link[/url].
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[DennisW]

[blue][size 2]Hey Paul, I read in Bass & Walleye Boats magazine, I think, that a strong pee stream does not necessarily indicate that your impellar is pumping enough water through your block to cool the motor. So with a failing impellar, you could still have a good pee stream but still not be cooling your motor sufficiently.[/size][/blue]

[blue][size 2]Teroy has the right idea--change it regularly and then you don't have to worry about it.[/size][/blue]

[WalleyePaul]

Changing it regularly sounds like very good commonsense what with it being rubber and all, don't usually last through the winter year in and out.

Anybody give me tips on how to get inside mercury to get where the impellar is? You can private message me if you are willing to come over and check my boat out, and show me physically where it is. One angler mentioned $15 for the impellar, where is that store?
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[Teroy]

I have a Chilton for my boat. I suggest you pick one up also, especially for a newer boat like yours. It not too awfully hard to change. Its in the lower part of your outboard.
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