Its possible that it's gummy, I bought one that had sat for about 4 years and the governor weights were stuck in it. it was an easy fix. I still have this pump if you'd like to buy it. I ran it until 2017 when the engine failed, then it sat in the car with fuel in it until about 1-2 years ago, since then it's been stored in my garage, it has a vanagon-style throttle lever on it