Impeller damage 100 hr

[Go Aweigh2452]

Took this photo of my impeller that was run dry for one minute (on purpose to see what would happen just prior to changing it out). The "set" you see was not related to the dry run. The impeller is still pliable but it had little to no contact with the pump housing. I'm surprised the engine did not show a high temp reading during normal operation. maybe the speed threw the blades out far enough to push enough water through the engine? I have no idea how the "set" could happen. There is no abnormal wear showing other than the "Set". This impeller had about 100 hours on it since July 07.
http://www.bremertonnjrotc.com/goaweighto/impeller/impeller.jpg

[Nehalennia]

So the pump housing is somewhat oval. Are you saying that at the constricted sides of the pump the veins were not touching the housing walls?

[Go Aweigh2452]

So the pump housing is somewhat oval. Are you saying that at the constricted sides of the pump the veins were not touching the housing walls?

yep, the impeller was actually free floating and not touching on most vanes, a couple were barely brushing on one area only... very weird. The only thing that makes some sense is a few months ago I sucked up a bunch of mud trying to get to a ramp that was in very shallow water and maybe the mud warped the blades? OR, maybe the impeller was an old one off the self when they built my motor (build date was June 07)???

[Nehalennia]

yep, the impeller was actually free floating and not touching on most vanes, a couple were barely brushing on one area only... very weird. The only thing that makes some sense is a few months ago I sucked up a bunch of mud trying to get to a ramp that was in very shallow water and maybe the mud warped the blades? OR, maybe the impeller was an old one off the self when they built my motor (build date was June 07)???

I doubt it was the mud, but the older impeller theory sounds more plausible.
I'll be picking up Nehalennia today along with a spare impeller.

[SomeSailor]

I don't think the "set" is as big a deal as you think. The vanes only need to wipe the walls to move water. The amount of water (and the pressure) these produce is probably very slight anyhow. All of the used impellers I've seen have that same "set" over time. They lose their supple nature pretty quickly I'd imagine.

[Stray Cat]

I don't think the "set" is as big a deal as you think. The vanes only need to wipe the walls to move water. The amount of water (and the pressure) these produce is probably very slight anyhow. All of the used impellers I've seen have that same "set" over time. They lose their supple nature pretty quickly I'd imagine.
I agree. I've taken various types of pumps apart after some what short running time (certainly less then 100 hours) and the vanes always have a set. I would bet that you could put in a new impeller and it would look like that after just a few hours. It's when they start to chunk and crack is when you should be worried.

[gpspowell]

When I picked up my 242 last year the dealer had fired up the boat out of the water (Why?). When I put it in it alarmed hot after about five minutes idling. When I pulled down the pump the impellarit came out in seven pieces. Only one vane was intact.