How do you replace a cylinoid?

Depends on what it is used on, most starter solnoids, on lawn mowers are mounted on a part of the frame, close to the starter, its a small round thing, with 2 post,s sticking out of the sides, and 1 or 2 small post on the bottom part, holding it to the frame, , just remove the wires, rembering where they were, and replace it,