How do I remove the original equipment bilge pump

[jonathanwsmith]

Hi - how do I remove the original equipment bilge pimp from a 1989 Mastercraft ProStar 190?
The original pump is yellow, I cannot see the brand or make, it is bright yellow and has a sticker on it that says model 2200. it looks like it may be clipped into a plastic base. It won't budge. any suggestions would be greatly appreciated. See picture at http://tumRblr.com/blog/theflyingboykin