PDA

View Full Version : Melted impellers


cordark615
04-12-2011, 09:21 PM
Why would the inside of the green ballast impellers be melted out? The guy we bought our boat from said he changed them to green,which he did, they were just melted. Thanks

coz
04-12-2011, 10:25 PM
Why would the inside of the green ballast impellers be melted out? The guy we bought our boat from said he changed them to green,which he did, they were just melted. Thanks

No water will do that.

milehigh970
04-12-2011, 10:37 PM
Yep.. Ran them dry..

cordark615
04-13-2011, 05:10 PM
How long do you think it would take to melt them running dry? Thirty seconds or ten minutes. The reason i am asking is because i dont want to do it.

east tx skier
04-13-2011, 05:52 PM
Closer to 30 seconds that to 10 minutes.

pmkkdx
04-13-2011, 06:21 PM
not sure on the ballast impellors, but on an engine impellor only about a minute, two tops, running dry ...

found that out when my wife forgot to kill the engine coming out of the lake shortly after we upgraded from the older louder '83 S&S to the much quieter '04 X2 ... top of the ramp when I started to towel down the boat, I felt vibration on the hull :confused: ... so I asked her "did you kill the engine?" ... she shrudded her shoulders and said "I dunno" ... next day out, noticed temp gauge running pretty hot at idle speeds upon unloading, we re-loaded immediately and headed home (I didn't have a spare impellor for that boat to do a replace on the fly)

Barefooter92
04-13-2011, 08:08 PM
not sure on the ballast impellors, but on an engine impellor only about a minute, two tops, running dry ...

found that out when my wife forgot to kill the engine coming out of the lake shortly after we upgraded from the older louder '83 S&S to the much quieter '04 X2 ... top of the ramp when I started to towel down the boat, I felt vibration on the hull :confused: ... so I asked her "did you kill the engine?" ... she shrudded her shoulders and said "I dunno" ... next day out, noticed temp gauge running pretty hot at idle speeds upon unloading, we re-loaded immediately and headed home (I didn't have a spare impellor for that boat to do a replace on the fly)

Bet you have a 35 dollar back up now:D

ttu
04-13-2011, 08:08 PM
Closer to 30 seconds that to 10 minutes.

i don't think they would melt that fast. i finally replaced mine this last season and they looked fine. i have run them up to 7-10 minutes dry in the past with no issues.

i am guessing maybe something else is wrong with the pumps.

cordark615
04-13-2011, 08:49 PM
I dont know, maybe his kids left it on. Maybe all night.:uglyhamme

east tx skier
04-13-2011, 09:21 PM
i don't think they would melt that fast. i finally replaced mine this last season and they looked fine. i have run them up to 7-10 minutes dry in the past with no issues.

i am guessing maybe something else is wrong with the pumps.

I don't have ballast pumps. But this past weekend, I started up and mistakenly ran my boat without the belt that turns the impeller in the pump housing. Noticed it pretty quick (matter of minutes), shut down, and got the belt on there. Ran it for maybe a minute after that and shut down when the heat spiked. I don't know how I toast an impeller that isn't turning. So I presume it got too hot without turning and when I did spin it, it fell apart quick.

Different circumstances for sure, but these things are not built to be run dry for long. Heat will kill them.

rand49er
04-13-2011, 10:19 PM
Guy I bought my boat from (two weeks ago) told me he changed the impeller and showed me the "old" one that had less than 200 hours. Had a big chunk out of one of the blades ... rest of it looked new. Not sure what would cause that.

east tx skier
04-13-2011, 10:34 PM
Heat and friction. Sounds like he changed it right before it all went downhill. Mine looked like a hockey puck.

nmcjr
04-13-2011, 11:51 PM
Yeah, its from running dry, but I think it might even be more than 10 minutes. Once after putting a friend onto an ambulance (unconscious, but turned out fine) I forgot to turn one of mine off until I got home, 2 hours later. The center was all melted out like you describe, and it was literally brand new that day, I felt like an idiot but was a little distracted to say the least! I've run them dry for 10 minutes since with no issues.

gotta_ski
04-14-2011, 12:34 AM
Eastie, I think yours was already toast that day or it went when you reconnected it from age. If it wasn't turning (being driven by the belt) and its a standoff belt driven pump, there is nothing to generate heat in the pump without it turning. I feel that for the heat from the motor to melt a non-rotating impeller it would have to be just about on fire. At those kind of temps I think the impeller would be the least of your concerns.

Dan K
04-14-2011, 08:04 AM
Eastie, maybe someone stole your impeller and replaced it with a hockey puck hoping you wouldn't notice right away. I agree with gottaski.

east tx skier
04-14-2011, 10:30 AM
Doubt it. It was a brand new impeller.

rem_pss308
04-14-2011, 10:48 AM
Yeah, its from running dry, but I think it might even be more than 10 minutes. Once after putting a friend onto an ambulance (unconscious, but turned out fine) I forgot to turn one of mine off until I got home, 2 hours later. The center was all melted out like you describe, and it was literally brand new that day, I felt like an idiot but was a little distracted to say the least! I've run them dry for 10 minutes since with no issues.

Dang if your engine ran with out water for two hours. Im sure there were more things melted than the impellar.

scott023
04-14-2011, 11:01 AM
Yeah, its from running dry, but I think it might even be more than 10 minutes. Once after putting a friend onto an ambulance (unconscious, but turned out fine) I forgot to turn one of mine off until I got home, 2 hours later. The center was all melted out like you describe, and it was literally brand new that day, I felt like an idiot but was a little distracted to say the least! I've run them dry for 10 minutes since with no issues.

So, you're saying you ran your motor out of water for two hours and the only negative result was a melted impeller? Doesn't sound right to me.

ttu
04-14-2011, 11:04 AM
So, you're saying you ran your motor out of water for two hours and the only negative result was a melted impeller? Doesn't sound right to me.

pretty sure he is referrring to his "ballast" impeller and not the engine impeller.

scott023
04-14-2011, 11:11 AM
pretty sure he is referrring to his "ballast" impeller and not the engine impeller.

I hope so. :rotf:

nmcjr
04-14-2011, 05:31 PM
No, the engine, I run Amsoil so it was fine--just kidding, yes, the ballast impeller.

east tx skier
04-14-2011, 06:56 PM
No, the engine, I run Amsoil so it was fine--just kidding, yes, the ballast impeller.

Nice. :D

/my mechanic suspects that the heat from the engine warmed up the pump housing enough to get the impeller blades to stick a bit. So when I got the belt on, i yanked them apart.

//I get one oops per season.