The only thing I've read, and I can't remember where at, was they supposedly know what the problem is. Either gas or some additives in the gas is soaking into the impeller causing it to swell and seize. If this is true or not, who knows. If this is the total answer it would seem to be a simple fix, just make the impellers out of something that wouldn't soak gas. Other than that haven't heard anything other than my recall notice.