Gentlemen, I have a 50 HP Yamaha in great shape on a nice Gregor which I just purchased. I believe it is a 1985. It came with a spare impeller. The motor pumps water well,I have used it only once. I would like to put the new impeller in as I do not know how old the one in it is. My question is do I need gaskets to do the job or can I get by without new ones?I see gaskets in the Iboats diagrams. Do I need new ones just to install a new inpeller? Thank You for your replies. I appreciate them.