Electric pump not pumping fan not cooling

It almost sounds like two unrelated issues. Unless that 360 is built to the max I would think that a high volume mechanical or a electric should work fine. I have a 360 running almost the same combo and switched from electric to mechanical with no issues at all. If your electric failed and mechanical doesn't perform well I would be looking at a clogged filter or something in the tank causing issues. Did you check the pressure with the mechanical also? You may only be running a 3psi with that too.