2003 Supra Launch

This may come across as a dumb question, but I was wondering if anyone else has had trouble after winterizing their boat with the ballast pumps. I've had issues with them before being gummed up and not pumping correctly.
Is this an issue that occurs regularly? And is there an easy way to get them cleaned out or is it just the fact that the pump is bad. I was also just starting it for the year so it was on the trailer during the time I was trying to get them to function correctly.
Thanks

Last year I had one pump that wouldn't work. Everything looked fine. I opened it up and the impeller looked fine, inside was smooth, etc. Tested it without the impeller and worked fine. Tested it with the impeller from the pump that worked and it worked and vice versa it didn't work. Finally inserted a new impeller and voila! it worked. There was nothing visible about the old impeller that caused the malfunction.

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