Unfortunately I made the mistake of thinking the squealing in my Pro Star 205 was from a worn belt I hadn't gotten around to replacing. After replacing the electronic ignition module that went out a couple of weeks ago, I was sitting at the doc doing the final timing adjustment and the impeller shredded itself completely. Luckily I was close enough to shut it down before the temp spiked too high. No damage other than to pride thank goodness.
I didn't realize how much noise it was actually making until we took it out with the new impeller last week. It's very quiet now.
New impeller at local dealership was $39 + tax, so not too bad.