How do I disassemble a Homelite 330 to replace intake boot?

The intake boot on my Homelite 330 has rotted out. I've got a new boot and started the disassembly, but I can't seem to separate the bottom from the top of the housing. Everything is loose but the fuel tank (or the boss that holds the rubber grommet in the back by the handle) won't allow enough clearance for final separation. What am I missing? I don't want to force anything and break the plastic fuel tank.