I have a new oil tank (old tank is cracked and leaking) but can't get the case apart to get to the old tank. I've removed all of the screws on the left side, as well as the pull rope assembly, and the case is loose but won't come off. It still feels as if something else is holding it and I don't want to pry any harder for fear of breaking something. What am I missing? Also, does anyone know where to find a shop manual for the Mac 3214? (I have the user manual but that does not help with disassembly.)