I had some issues with my 2002 mercury 3.3 hp 2 stroke with water pumping but after a simple impeller change I thought it was sorted, it stopped pumping water again and when I opened lu the impeller housing had blown apart, the shaft just below the spline the connects to the engine was groved deep as well and seemed to have gotten very hot as the metal had changed colour. The impeller itself was in fine condition not a problem but the housing above it smashed. I took it to an outboard guy who had not seen the impeller housing smashed before (just my luck) and thought it could be oil seals gone bad and caused the grove, I decided to chance it and try it with new impeller housing on ran it briefly and the water came through tell tale again, put into gear the (engine was running erratic not catching revs very well at all) water stopped coming out tell tale again shortly after and when took off lu the prop shaft had completely sheared off at the groove point, so engine is now in for strip down new seals gaskets the works prop shaft etc, seems too big a job for me to tackle myself and have left it with the outboard guy who knows his stuff. I was just wondering has anybody seen or heard of such problems before? Seems to be a rare one as there a metal surround on the inside where impeller goes? How worried should I be? It just seemed odd the impeller housing was smashed and what would cause the grove? Would the oil seal actually cause that? Any input welcomed, cheers Jon