how fast can a water pump fail?

[lekmedm]

Extremely frustrated here...

I've gone through a lot of pain this season with the cooling system on my OMC equipped boat. So one of the things I did this year was replace the water pump components in my cobra outdrive including impellar, plate, and gasket. Once I had all my cooliing issues squared away, I was able to run the boat for a half an hour at 170* on muffs. So now the boat is in the water and when I finally had time to go down and take it out, it heated up to 220*!!!. I took the hose off the power steering cooler to check for water flow, and there was practically no flow! Now, what the hell is that all about??? The boat didn't have a chance to go out anywhere and the pump failed? Could there be some other problem? I'd like to be relatively prepared with solutions because it will cost me $200 just to have the boat pulled out so I can work on the outdrive.

 

[dubs283]

Re: how fast can a water pump fail?

if you ran the motor without a water supply, the impeller can fail quite quickly.

should check the cooling stystem from the water inlet at the transom, through the cooler, up to the thermostat hsg for old impeller chunks, weeds, debris, etc.

 

[cr2k]

Re: how fast can a water pump fail?

Yes, pull the hose off the other end as well and look for debris, most likely old impeller pieces.

Also check the SS cup in your impeller housing, If its cocked to one side replace the whole thing.

Oh yes, your original question...In as little as 15 seconds!

There are impellers out there (some silicone nitral things) that are guaranteed to run dry for 30 minutes. Haven't tried one of these yet.

 

[HT32BSX115]

Re: how fast can a water pump fail?

I took the hose off the power steering cooler to check for water flow, and there was practically no flow! Now, what the hell is that all about???

OMC 460..... I used to have one of those.....


You have a power steering cooler AND an oil cooler.

The raw water supply from the transom usually goes to one or the other (both) and then goes to the thermostat housing OR the closed cooling heat exchanger (if equipped)

If you have had a previous raw water pump failure (1 or more) You could have impeller fragments in either the oil cooler or the PS cooler. If your PS cooler is like the one I still have that came off of my 460, it's just a simple tube inside and would probably pass the fragments.

If the oil cooler is before the PS cooler, then you probably have fragments from the last impeller failure (or previous failures) clogging it. They could choke the flow down to a
dribble.

You can easily check the raw water pump flow by disconnecting the hose that comes from the transom plate (before it goes to any oil or ps coolers)

connect a longer hose to it so you don't make a mess inside.

If you still do not have any flow, then either the hose itself is clogged with pump remnants (which is unlikely) Or the pump has failed. (again)


I'm going to assume that you did not at any time run it dry for even a few seconds. and/or you had water on it with muffs or the drive was submerged before you started it.


Sorry for your frustration....



Rick

 

[45Auto]

Re: how fast can a water pump fail?

Running the boat out of the water (on muffs) puts no load on the engine, so it takes very little water flow to keep the engine cool. When you actually use the engine to move 4 or 5 tons of boat, it puts MUCH more load on it and requires MUCH more water to cool it. As the eqrlier posters said, you either have something blocking your cooling system or a bad pump.

 

[lekmedm]

Re: how fast can a water pump fail?

Thanks everyone. Like I said in my original post, I had everything running great on muffs before the boat went into the water and holding a temp of 170*. I suppose the dopes at the marina could have done something when they put the boat in the water. I wasn't around for that.

You have a power steering cooler AND an oil cooler.

The raw water supply from the transom usually goes to one or the other (both) and then goes to the thermostat housing OR the closed cooling heat exchanger (if equipped)

Rick, I'm not sure about the oil cooler (I'll check my manual), but, as usual, you are bang-on with the rest of the setup. I disconnected the hose after the PS pump cooler, cranked the engine, and bascially got no flow. I did the same test earlier on land on muffs and got good flow. Regardless if parts are stuck in the PS pump cooler, I need to get at the outdrive to inspect/replace the water pump. That means pulling me out of the water.

 

[HT32BSX115]

Re: how fast can a water pump fail?

You manual might not indicate exactly what you have (although I don't think ANY BB engine should be without an oil cooler).


You should be able to just follow the hose from the transom plate..... where it slides over the pipe. (#68 below), to each oil cooler. There should be a hose that goes from one to the other and then to the T-stat housing. (They're in "series". )

Sometimes you won't have enough debris in there to completely impede water flow but there'll be enough to restrict it so that you'll get an over heat at the higher power settings.