merc 5.7L how long to run with no water

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bolo789

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Aug 26, 2002
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how long can one runs a engine with no water supply coming to it, only the water already in the block.??? no drive on, no water hose connect. i just want to fog the engine.
 
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walleyehed

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Re: merc 5.7L how long to run with no water

That was a good thread...it only takes a few seconds to melt an impellor, but ya still see guys doin' it, and we love installing new impellors for them...keeps us going.. :D
 
FreeBeeTony

FreeBeeTony

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Re: merc 5.7L how long to run with no water

he states the drive is off.........i imagine it could be run long enough to fog it.
 
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bolo789

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Re: merc 5.7L how long to run with no water

yea the drive is not install just want to run it an fog it. how long a chance i can take with out problems??
 
Bt Doctur

Bt Doctur

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Re: merc 5.7L how long to run with no water

to be safe, use a hose from a washing machine cut in half, insert into water inlet hole,fog motor, drain block and manifolds.If you run the motor too long dry youll melt the rubber hoses on the exaust "Y" pipe.
 
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trog100

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Dec 1, 2004
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Re: merc 5.7L how long to run with no water

course u could do it the none lazymans way.. remove the plugs and squirt some oil directly into the cylinders then spin the engine over a few times on the starter.. remove a coil wire or something to make sure it dosnt fire up else it will blow all the oil out..<br /><br />trog100
 
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walleyehed

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Re: merc 5.7L how long to run with no water

Didn't catch the drive being off....that makes a heck of a difference, but I would suggest the above of pulling plugs and oiling, and turn through a few times.
 
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crazy charlie

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May 22, 2003
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Re: merc 5.7L how long to run with no water

Bolo,as long as the drive is off there is no problem running the motor a a few minutes w/o water to get it fogged.<br />keep an eye on the temp while fogging,but get it done as soon as the motor is cranked up,dont wait for a minute before you hop to the fogging.I have done this a time or two before and have run the motor for as long as 5 minutes w/o any significant temp rise.There is an attachment available to get garden hose water into the bellhousing.It screws onto the mounting stud next to the water inlet .You can also just have some one hold a garden hose up against the inlet to force some water in.My guess is that you have already drained the block and dont want to do it again and if that is the case, go ahead and crank up the motor and fog it within a few minutes and get it done.Charlie
 
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Richard Petersen

Senior Chief Petty Officer
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Dec 17, 2004
Messages
778
Re: merc 5.7L how long to run with no water

The newer impellors have have synthetics in them that take "SETS" and don't like dry runs. Old Johnson Seahorses could do that stuff- no real problem! Run only in water, or listen to overheat alarms.
 
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Richard Petersen

Senior Chief Petty Officer
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Dec 17, 2004
Messages
778
Re: merc 5.7L how long to run with no water

Oh --If you run in water with lime, calcium- you will boil the water away and make cements. Watercooled exhausts are a great place to boil water and make white cement. Boil water in a pot on the stove - white cement.
 
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bolo789

Petty Officer 1st Class
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Re: merc 5.7L how long to run with no water

thanks guys i will try just keep an eye on the temp guage<br /><br /><br />thanks again
 
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DHPMARINE

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Dec 16, 2003
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Re: merc 5.7L how long to run with no water

My concern would be running it long enough to get stabilizer thru the carb.<br /><br />DHP
 
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newport dave

Chief Petty Officer
Joined
Nov 21, 2004
Messages
458
Re: merc 5.7L how long to run with no water

I wouldn't recommend running the engine without water at all! <br /><br />I would agree that possible deposits from boiling the water in the block could be a bad thing. <br /><br />However, I think that the most likely danger would be burning the rubber components of the exhaust system. Not only the hoses as mentioned in a earlier post, but the internal rubber coated exhaust shutters that prevent water from flowing up through the exhaust and into the engine. <br /><br />You won't even know they are damaged (you can't see them without pulling the risers) until it is too late. <br /><br />Dave
 
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