Hello, I am new to boating and have bought a old 16ft fiberglass boat with a 25hp Mariner. The motor runs ok, but needs a prop and a tune up. I would also like to replace the water pump ( don't know when it was last changed). The data tag is gone off the side of the motor. The only numbers that i have are off a hand writen note from many years ago 318161. How would I check to see if these are good numbers? I've gone to the sites that I have found on here, but don't see a match. The motor is a Mariner 25hp, 20 inch shaft, pull start. Is there another way to tell the year, ie somewhere else on the motor? Any help or guidance would be great. Thanks