Help with year and impeller change Mariner 15HP

[Nickmurguia]

Just picked up a sweet little boat with a very nice 15HPmariner on it (tiller). I took it out this past weekend and it fired right up and ran like a champ, but when I flushed it at home I noticed the pisser was very hot to touch. Too hot to touch at times. My question is what year is my motor and where can I find the correct impeller to swap it out. Any help with doing this job would also be appreciated. Instructions... I've never done it, but I hear it isn't too bad

Serial number is 0C179577