I just purchased a L185 for a "project" from my neighbor. It has been sitting in the field for a bout a year and a half since it was last running. It appears I am not getting any fuel into the cylinders or out of the injection pump. My question is concerning the injection pump. Can they get "gummed" up like a gasoline carb might get? Can they be cleaned? Do they go bad? Can you rebuild them? How do I know for sure that the injection pump is not working?