Water pump question

Was working on getting everything ready for spring and hooked my boat up to the garden hose to crank it up. For reference I hooked it directly to the v-drive inlet. I noticed that when I turned the hose on (engine off) the water pump was making a whistling noise like air was being pushed out of the system. Once the air was pushed out, it looked like a little water was coming out of the engine side of the water pump. Once I started the boat it stopped leaked and looked completely fine. Is this normal? I'm assuming the pressure of my supply water was too much and forced water out of the weakest seal. It definitely looked like it was on the engine side though were the shaft pushes through and not on the impeller cover plate side.

I can't speak if its normal or not, I will say a garden hose typically has 30-60 psi of pressure depending on your area and city pressure, the typical automotive system is 15psi. be careful when using the garden hose at full pressure and not having the engine running.

Fake a lake will leak water out the sides of the hull seal so it doesn't over pressurize the engine intake.

No need to worry though, if the boat is running and no water was leaking out then I wouldn't worry to much. I would how ever watch it next time your on the lake and its at operating temp. No water should be leaking, and if there is then get it fixed.

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Originally Posted by smitty75

I noticed that when I turned the hose on (engine off) the water pump was making a whistling noise like air was being pushed out of the system.

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When I do this, the noise is like air and water squishing around until the air is pushed out. I wouldn't call it a "whistle". Am I describing the sound you hear?

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Originally Posted by smitty75

Once the air was pushed out, it looked like a little water was coming out of the engine side of the water pump. Once I started the boat it stopped leaked and looked completely fine

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I'm not sure exactly what you mean by "water coming out of the engine side of the water pump". Do you mean that water is simply going through the pump as in normal operation? That is normal. When I run the hose, water will eventually start coming out through the exhaust. But based on your comment that the "leak" stops, it sounds like it is leaking from somewhere else which is not normal. Maybe this is where you are getting more of a true "whistle" sound from? I'm with Mike though, it's probably in the non-critical category if it doesn't leak under normal operation (or even if it leaked a little - that would just be extra water in the bilge to be pumped out) I would fix it when convenient but I wouldn't lose a day on the water for it.

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Originally Posted by mmandley

I can't speak if its normal or not, I will say a garden hose typically has 30-60 psi of pressure depending on your area and city pressure, the typical automotive system is 15psi. be careful when using the garden hose at full pressure and not having the engine running.

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I fully agree that you don't want to over-pressurize an automotive cooling system. But I don't think you need to worry about this in an open-loop marine system. There would be higher than normal operating pressures before both the raw-water and the engine-water pumps but that's just hoses which can handle these pressures. Once the water is into the water jacket, it is free to escape through the exhaust so the pressure would be effectively 0. I may be wrong, but I've never worried about it when working on my boat.

Thanks for the information. The leak I was describing was actually water squirting out of the pump in the area where the shaft passes through. I'm guessing there is an o-ring of some sort in there that couldn't handle the pressure of the water supply. I just put a new impeller in, so maybe that was restricting the flow enough for the pressure the build up when the boat wasn't started. Once I started the boat the leak stopped and everything looked fine. I let it run for about 15 minutes and it seemed fine.

That's the classic failure point for water pumps. If you are ever loosing coolant from your car, that's a good place to look for a trail of dried coolant. I would say that your water pump is going bad. This is in the non-critical category. Usually, they leak undetected for a while and then eventually fail catastrophically, usually after you turn off the engine, all of the coolant leaks out of the engine. In a car, the leak is a big deal because you have a limited amount of coolant so you can't afford to loose much. In a boat, you've got plenty of coolant :)

This is about as cheap and easy as engine repairs get. If you are even remotely handy with a wrench, you can do it. Add it to your rainy day project list. It's probably about a $50 part. This is a case where an automotive part is just fine, the trick is figuring out which one. You may need to look at pictures to find the right one or take it to the parts store and ask for help. I usually have good luck telling them to start with an '85 Camaro. If you need instructions, just go to the library and check out a repair manual for a GM with the 350, or pretty much any American car/truck will be close enough to figure it out.

this happened to me last year when I was getting ready to put the boat away and changed all the fluids. I heard a "whinning" sound and saw some water leaking out, but can't remember where it was coming from. I assumed it was because of too much pressure. I figured I would be changing the impeller this year and then run it up at the lake early this year and see if there was anything still leaking and then decide.

I actually talked to a couple service places and they all seemed to think it was from the pressure of the hose. They said not to worry about it unless it starts making noise or the leaking continues without the hose pressure. I'm hoping to hit the lake Saturday so I will know for sure.

Had a chance to get out on the lake yesterday and had zero issues with the water pump. No leaks or noise and held the temp right around 160-170.