Thread: Petrol powered pump sunk

How clean was the water that got into the sump ? If fine silt or dirt got in, I would change my approach. Probably pull it down to clean it properly.
If it’s clean water, once it was drained fully, I would fill with new oil and run it for a few minutes, and check the oil, if it’s milky looking, drain the oil and refill again. If it’s still clean looking oil, or if you had to change it again, run it for an hour or so to get it fully hot to try and evaporate any moisture still in there. Then change the oil again.
Just run the water back into the dam while you are running it, unless you need to supply water to somewhere else.
I am assuming it doesn’t have an oil filter, if it does, you will have to change that too.

Thanks Brad . Good thinking !
It’s nice clean water . A bit tannin coloured or something to do with coal under us I was told . It’s clear but brown like tea with no milk . It’s the water table filtering in from below and rising out the top and through the grass . Hasn’t done it for many years . So no silt or dirt .

I will do the oil and run it as you say and take a look after a few minutes .

To get it out I just cut the pipes off with the chain saw . As it wont be going back there again . And it looked like removing the cold stuck on fittings wasn’t going to be easy . Unfortunately the 40000 lt concrete tank it supplied has just cracked as well .That’s finished unless there is a way of an easy major repair . So we’re thinking new tank up on a high spot and a solar pump .
I just happened to take pictures to show my son .
A picture of pump where it sat , usually dry , and under cover .

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Forgot to ask .
How long can petrol powered pumps safely run with no water going through them ?
I suppose it’s the water running through that keeps the bearings cool around the impeller that’s the problem ?
So not longer that a minute ?

Originally Posted by auscab

Forgot to ask .
How long can petrol powered pumps safely run with no water going through them ?
I suppose it’s the water running through that keeps the bearings cool around the impeller that’s the problem ?
So not longer that a minute ?

Sorry, but I can’t give you a definite answer on that. Maybe someone with experience with water pumps can advise.
Myself, I would be finding a way to have it pumping water while it’s running. If you can’t suck water out of the dam to run it, do you have a tank or trough that you can suck out of and pump back into, surely it’s possible with a bit of poly pipe and a few fittings.

It's not the bearing that's the problem but the water seal that stops the pump pushing water into the motor.

The seal is water lubricated and if you run it dry it will wear out very quickly.

Fill the pump with water and plumb the output back into the inlet. Stop the pump when the water starts to get hot.

Before filling the pump with new oil give it a quick flush with some diesel.

You don’t have a photo up of the pump. The job of the mechanical seal is to keep the water in the pump and the motor seperate. This can heat up and cause problems in under a minute depending on the design of pump.
A rule of thumb is 5% of flow minimum for cooling. If the pump capacity is 100 lpm you need 5 lpm to avoid damage.

put up a picture please, it could be as simple as pouring water from a bucket into the inlet or outlet.

cheers

Originally Posted by Bohdan

It's not the bearing that's the problem but the water seal that stops the pump pushing water into the motor.

The seal is water lubricated and if you run it dry it will wear out very quickly.

Fill the pump with water and plumb the output back into the inlet. Stop the pump when the water starts to get hot.

Before filling the pump with new oil give it a quick flush with some diesel.

Ah OK , its a seal that's got to be looked after . Good to know .

Yeah I can give the diesel a go . And Ill have to re fit it to one of my tanks close to the shed .

Originally Posted by Wrongwayfirst

You don’t have a photo up of the pump. The job of the mechanical seal is to keep the water in the pump and the motor seperate. This can heat up and cause problems in under a minute depending on the design of pump.
A rule of thumb is 5% of flow minimum for cooling. If the pump capacity is 100 lpm you need 5 lpm to avoid damage.

put up a picture please, it could be as simple as pouring water from a bucket into the inlet or outlet.

cheers

Yep that's good to know thanks . I could fit to my tanks at shed or even just run a hose through it . Come to think of it Ive got a Fire pump sitting with 1000 lt ready to go so I may use that instead of the slow flow gravity tank . That'll be well above 5%.

Ill throw up some pics next .
Its just a cheap ebay thing as I said but its done some work .
It did get a bit hard to start at times in cold weather at times and would run very rough when it did finally start until it heated up . Then it was fine .

Apart from being cheap all over with these things . Is there a common part that lets them down and kills them ?

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It is what they refer to as a self priming pump and you can simply run the garden hose into the suction line and have it on low flow for your testing, drying cleaning. The housing holds a good volume of water and with the design the majority of water is above the seal keeping it lubricated.

if you think it’s not enough flow just feel the water every 30 minutes or so.

cheers

I got a submerged motor running again and thought it was all good only to find it seized when I went to use it a month or so later so give it a good long run so it gets nice and hot and dries out and replace the lubricants.