Ok Guys... I made this thread in hoping to getting to the root of the problem, thinking it was just one thing (sand sucked up somehow). However, after all of the helpful tips, advice and discussion, it has spurred quite the brainstorm.
I called today and ordered 2 new impeller kits. Ill tell you why.
The last owner (who Ive got a call in to right now and am awaiting a return call) only had the boat 1 season. The only maintenance he did was change the engine oil and outdrive lube. I just tuned up the boat and it had ALL original parts, the spark plug wires were quite aged. I mean I only have 106 hours on the engines now BUT Im going to bet you all RIGHT NOW that the impellers are originals from 1997

Im going off a hunch. If the last owner(s) wouldnt do something as easy as change the plugs/wires/cap/rotor, why should I imagine they would contort their bodies to change the impellers?!
Plus although I swear the pieces are larger size granules of sand, what somebody said lit a bulb above my head. I have never taken all the pieces that have come out from the stuck t-stats and rubbed them between my fingers. I manually open the t-stat and flush it out with water in the kitchen sink, into a bowl. Its possible that some of those pieces are rubber. Than again, its possible they arent as well.
Either way, I ordered 2 volvo penta impeller kits today. As soon as they arrive, Im changing them and will update this thread as to the condition of the old impellers and ((maybe)) if that was the cause, or maybe when I take the impeller housing off, I will find sand? I dont know but I will keep you all posted!