So I've had an 18 for years but she just got too tired and busted up. Picked up what appears to be a super low hour matching motor to my old one. I've been going through it thoroughly to clean it up and make it reliable. My question is I found what looked to be 2 o rings in the end if the crank where the driveshft splines in to. Looks exactly like the o ring that goes in the Grove on the driveshaft. But there's no way an old one could have slipped off and made its way in to there during a past water pump change. Especially not 2. So are these prone to a driveshaft rattle? Splines are dead tight in there. Old mechanics trick to keep it quiet? But I can't see how you would get them in there without pulling the powered and it looked to have never been off. I can't see 2 o rings stuffed up above the driveshaft being factory omc. but I also can't see how someone got them in there, or why they would have. Any thing you guys know that I don't? Almost seems like a smart idea to keep the driveshaft pre loaded in to the lower end a bit. 