OK i have a problem with my 1959 mark35a, it kept overheating so i ordered an impeller for it, so i got to taken it apart and i droped the lowest unit on it, well i dont see an impellor like i was instructed i would, also if anyone is familiar with this engine, right in front of the 2 mounting studs on the lower unit there is a pocket that goes all the way down to the bottome well its full of what looks like grit sand and oily dirt, My question is Where is the impellor and how do i replace it???? i cannot afford an owners manual next question is what is the little pocket where i found all the dirt, IT is right next to the little shaft in the front. is it ok to vacumn it all out? any help would be gladly appriciated please email me as i probably wont find this website again ....thanks again Jered 