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Running a motor without water


Plumb

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Hi all , took my boat for a run on Sunday for a test after a service, ran like dream now that I drained the petrol and re fueled with fresh stuff....

Any way for one reason and another I couldn't flush the motor out till this afternoon ( 48 hrs). After 10 - 12 seconds no water was shooting out the back, I switched off the motor and pulled out the "sprayer" on the back and used a hose to force water in, a small amount came out the intake. Then I tried to re flush for about 10 seconds but still no water out the back.

How long could I run the motor before I cause damage? I've never timed how long it takes to come out before I do recall it usually takes a few seconds.

It's a Johnson 115. 2005 model. It has over heat alarms ect

Cheers Luke

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Hey mate,

From the time you start your engine it should only take a second or two for water to start running through. You should not continue to run the engine if water does not pass through (you don't want to get to the stage where the alarms turn on).

Some of the problems include:

- A build up of salt which has blocked your lines. However, if this happened it would probably have built up over time and the engine would have been struggling while you were running it and probably would have overheated.

- You have a blockage in the line, which should have been avoided from the strainer at the intake location (check that is not damaged)

- Your impellor has failed and you need a new one

- The rubber seals in your impellor housing have failed and you are losing water

- Your hose pressure/seal around your water intake is insufficient and you are not getting adequate pressur eto allow water to pass through the engine.

If you submerse your engine leg in either salt water or a deep barrel of water to save you going to the ramp (to the depth it would usually be when you have your engine in the water) and the engine fails to pump water it would be your impellor/rubber seals.

Hope this helps.

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Hey mate,

From the time you start your engine it should only take a second or two for water to start running through. You should not continue to run the engine if water does not pass through (you don't want to get to the stage where the alarms turn on).

Some of the problems include:

- A build up of salt which has blocked your lines. However, if this happened it would probably have built up over time and the engine would have been struggling while you were running it and probably would have overheated.

- You have a blockage in the line, which should have been avoided from the strainer at the intake location (check that is not damaged)

- Your impellor has failed and you need a new one

- The rubber seals in your impellor housing have failed and you are losing water

- Your hose pressure/seal around your water intake is insufficient and you are not getting adequate pressur eto allow water to pass through the engine.

If you submerse your engine leg in either salt water or a deep barrel of water to save you going to the ramp (to the depth it would usually be when you have your engine in the water) and the engine fails to pump water it would be your impellor/rubber seals.

Hope this helps.

thanks for the quick reply, I thought 10 seconds was to long, I think the impeller Was replaced when it was serviced is it a rubber cog looking piece? I'll try it in a tub tomorrow arvo and give the mechanic a call in the mean time.

Cheers

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thanks for the quick reply, I thought 10 seconds was to long, I think the impeller Was replaced when it was serviced is it a rubber cog looking piece? I'll try it in a tub tomorrow arvo and give the mechanic a call in the mean time.

Cheers

No worries mate,

The rubber piece i am referring to is an "O" ring. I have spoken to several mechanics and often they inspect impellors for wear and may not actually replace it. Check on your service reciept to see if you were charged for the part (which would mean it is changed).

How long ago was your engine serviced? Impellor/seal failure can result from being exposed to the elements even though you are not clocking up many hours on the engine

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No worries mate,

The rubber piece i am referring to is an "O" ring. I have spoken to several mechanics and often they inspect impellors for wear and may not actually replace it. Check on your service reciept to see if you were charged for the part (which would mean it is changed).

How long ago was your engine serviced? Impellor/seal failure can result from being exposed to the elements even though you are not clocking up many hours on the engine

It was only serviced on wendsday, but prior to that not used for 4 mths, hence ths issue with the fuel, ran great on Sunday though...

I Better call themechanic tomorrow

Cheers

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Turns out it was my ear muffs... Reverted to an old set and no dramas. I Feel like a bit of a goose now...

Cheers

You will damage the water pump by running it dry, impeller and housing, the engine can run for a minute or so without overheating.

If you ever watched jetkis they run them without water when they come out to get rid of the water in the exhaust so it dosn't go in the crancase.

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You will damage the water pump by running it dry, impeller and housing, the engine can run for a minute or so without overheating.

If you ever watched jetkis they run them without water when they come out to get rid of the water in the exhaust so it dosn't go in the crancase.

cheers I thought 30-60 sec would have been ok but didn't want to risk it, so I stopped after 10 hence the post

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