I just came across a video on YouTube giving some good tips on servicing a Jabsco marine head. He as some good tricks for making the job less messy. However, at the end he recommends using olive oil for lubricating, which some people disagree with, but otherwise its a nicely done video. Just thought I'd pass it along!
https://www.youtube.com/watch?v=14mkaCgEkzY&ab_channel=TheBoatCheat (https://www.youtube.com/watch?v=14mkaCgEkzY&ab_channel=TheBoatCheat)