How long can a motor run out of water before impeller damage?

[possom813]

Last night my motor fired up on it's own(think I've got that solved)

It ran, out of water, for about 20-25 seconds before I made it out of the house and to the boat to kill it with the grounding switch(grounds out everything)

I found out, today, that a ground wire was actually a hot wire and got put in the wrong spot, accidentally, when I replaced the starter yesterday. So that's fixed.

Now I'm just worried about the impeller. I'm fixing to drag a 55 gallon drum around to fired it up with, just wondering though.

 

[stackz]

Re: How long can a motor run out of water before impeller damage?

might be lucky, might not. had an impeller that worked still after 2 minutes of run time. had one that went out 5 seconds after cranking up.

its rubber inside a dry housing. friction will heat it up and melt/deform it. you may still get a pee stream but it probably wont be nearly as strong.

 

[RogersJetboat454]

Re: How long can a motor run out of water before impeller damage?

Last night my motor fired up on it's own(think I've got that solved)

It ran, out of water, for about 20-25 seconds before I made it out of the house and to the boat to kill it with the grounding switch(grounds out everything)

I found out, today, that a ground wire was actually a hot wire and got put in the wrong spot, accidentally, when I replaced the starter yesterday. So that's fixed.

Now I'm just worried about the impeller. I'm fixing to drag a 55 gallon drum around to fired it up with, just wondering though.

20-25 seconds is about all it needs to be toast. I would be putting a new one in.

 

[possom813]

Re: How long can a motor run out of water before impeller damage?

I may have gotten lucky, I just put it in the barrel full of water and it's still pumping like it was, pretty decent stream.

It still had some water in it because we'd just brought it in from the lake a couple of hours prior to it firing up. So maybe that saved it.

 

[ajgraz]

Re: How long can a motor run out of water before impeller damage?

Sounds like you did get lucky. Merely bumping the starter for a fraction of a second out of water can ruin an impeller.

 

[firstboatbuild]

Re: How long can a motor run out of water before impeller damage?

might of gotten lucky. Though even if it seems to work in the barrell i would still go ahead a replace it. Not worth the risk that at this point it could be minor damage and it completly fails while on the water. Id rather replace a $20 part than a new powerhead.

 

[possom813]

Re: How long can a motor run out of water before impeller damage?

I don't know. I started it today in the barrel and it takes about 2 minutes(like always) for it to start misting and about another minute until it starts to stream.

Same way it's always been. But, if it burns up, gives me and excuse to get a shiny new Mercury

 

[HT32BSX115]

Re: How long can a motor run out of water before impeller damage?

It ran, out of water, for about 20-25 seconds before I made it out of the house and to the boat to kill it with the grounding switch(grounds out everything)

Howdy,


For the record AND for people wondering.................DO NOT EVER........ INTENTIIONALLY run a raw water pump dry!! (EVER!!!)

Here's one with only 20hrs on it, that ran dry for only a min or so.....(muffs fell off!!)

(I know you did not do this)

Now.......since your raw water pump DID run dry, you should change it......cheep insurance......


Regards,


Rick

 

[5150abf]

Re: How long can a motor run out of water before impeller damage?

I think it was bad before this happened, it shouldn't take 2 minutes for it to pump water, it shoud be pumping within seconds of starting, with my engine by the time it starts and I turn my head to check it is flowing already.

Its your wallet and you seem to want a new engine anyhow but you should change it.

 

[possom813]

Re: How long can a motor run out of water before impeller damage?

I'm going to take a short video of it in the morning of what it's doing. It starts to kind of steam in a few seconds, then starts sputtering water out like it has been since I've had it.

"Supposedly" it had a new impeller installed before I traded for it.

All in all though, it doesn't appear to be too difficult to change the pump out. Although, in the book, I can't seem to find what holds the driveshaft in under the powerhead, unless I overlooked it?

But, from what I gathered, buy the kit with the new o-rings for the shaft and take the shift wires loose and pull them through(not digging that idea) and pop off the impeller/waterpump top, carefully. Take off the old impeller, slide the new one on with a light weight oil, reassemble.

Shouldn't be more than an hour or so, being careful.

 

[emoney]

Re: How long can a motor run out of water before impeller damage?

Now you're thinkin'!

 

[Mi duckdown]

Re: How long can a motor run out of water before impeller damage?

My question IS. How in the heck did the motor start up by itself?
The kids.???

 

[Sixmark]

Re: How long can a motor run out of water before impeller damage?

Howdy,


For the record AND for people wondering.................DO NOT EVER........ INTENTIIONALLY run a raw water pump dry!! (EVER!!!)

Here's one with only 20hrs on it, that ran dry for only a min or so.....(muffs fell off!!)

(I know you did not do this)

Now.......since your raw water pump DID run dry, you should change it......cheep insurance......


Regards,


Rick

oddly enough that looks like the calamari I got at a restaurant one time

 

[Bamaman1]

Re: How long can a motor run out of water before impeller damage?

Pictures speak. 25-30 seconds. Otherwise, go to WalMart and purchase a water cuff to get water to it.

 

[bassman284]

Re: How long can a motor run out of water before impeller damage?

I think it was bad before this happened, it shouldn't take 2 minutes for it to pump water, it shoud be pumping within seconds of starting, with my engine by the time it starts and I turn my head to check it is flowing already.

Its your wallet and you seem to want a new engine anyhow but you should change it.

Agree. If mine ever took more than 3 or 4 seconds to start peeing I'd freak.

 

[HT32BSX115]

Re: How long can a motor run out of water before impeller damage?

oddly enough that looks like the calamari I got at a restaurant one time

I think calamari can run out of water a little longer though........

 

[444]

Re: How long can a motor run out of water before impeller damage?

I agree, just change it. They are so cheap to buy you'd be stupid not to change it. If you don't know how to change it this is the perfect time to learn. It's really not hard at all. My motors also start pumping water within seconds of the engine firing. I'd be very worried if mine took minutes to start peeing!

 

[robert graham]

Re: How long can a motor run out of water before impeller damage?

If you ever notice how tight the rubber impellar is packed into that stainless steel cup, then you know it won't take long for it to bulid up enough heat to damage it. I'd say running dry for 20+ seconds would most likely fry that impellar. Better change it and not take a chance. And you're just going to worry about it if you don't. Good Luck!

 

[sw33ttooth]

Re: How long can a motor run out of water before impeller damage?

on another note i took a boat out on the water to fry an engine once was a 50 horse merc from the 70's i beat on that thing full thottle for maybe 20-30 minuites to blow it up then got my friend to tow me back to shore i wouldnt worry about engine damage but if the impellor doesn't thow a strong stream i'd replace it should be done every 2-3 years any way so then you know your good.

 

[possom813]

Re: How long can a motor run out of water before impeller damage?

The impeller is on order, along with a few odds and ends to purty it up a bit.