A different kind of impeller failure

Welp, after 12 years of ownership and hundreds of hours on dozens of lakes, we finally had an impeller failure and overheated our beloved 2000 SN w/GT40. My track record of being an amazing inboard owner is totally messed up now. The boat's fine though the smell of fiberglass resin behind the boat as the skier certainly had me concerned for sure.

First, the story, because it's ridiculous: The night before this we did a lake cruise with the boat at idle for about an hour. This would have been a great time for the impeller to fail, and of course it did not. The next morning we decide to deploy the slalom course, which I do about once a year up north at the cabin. Of course everything is fine for that 30 minutes of deploying the course. I have Beth ski first, and the boat is fine. Perfect conditions, stars and moons aligning with the lake quiet and no wind. Truly a heavenly morning, the best of the best, the spice of life, what it's all about. After her set, I jump on the platform and hop in, ready to take it all in and enjoy it.

Beth starts up the boat and hits the throttle and as I pull out of the water I notice the boat sounds different, seems a bit steamy, and I'll be damned if it didn't smell a bit like burning plastic back there. I damn well knew what happened, but in the back of my mind I thought maybe I was just being paranoid and perhaps everything was fine. Maybe I was hearing things, maybe somebody was burning plastic on the lake. 34.2mph, through the gates, SLOW system kicked in by 4 ball and we swam it in. Was running a nice tight line and perfect times up until then.

By the time I swapped the impeller the wind kicked up and the lake lit up with tubers so that was that.

Upon close inspection the impeller had a hub separation failure. This is the second time this has happened to me, the first time was in the same pump on the 83 MC. The vanes all appear fine and the impeller simply separates at the hub for a total and instant failure. I have no idea how old this impeller is so I'm guessing 2-5 seasons. I've had too many boats so I've lost track. I'd been on the Hollywood/Pete "every year is too often" kick but this failure has me wondering. Totally ruined the morning.

The cut in the impeller is from me cutting it post-removal.

I have seen where the hub disbonded from the rubber but always felt it was due to an overheat (run dry) first causing heat.


Joel,
How weedy is that lake of yours this year?

M3Fan wrote: Notice it's not even a bonding failure- the rubber actually tears off of the hub as there is a lot of residual rubber still on there.

Joel,
I shouldn't have used the term disbonding. I feel that impeller ran hot and the reason I asked weeds and them plugging up the intake.

I buy the Sherwood impeller kits for about $25. For me, it's cheap insurance. My impeller gets changed out every spring. Overkill? Perhaps. Peace-of-mind? Yup. NEVER had an over-heating issue.

JQ