Mobile construction equipment with drive motor and fuel tank

The mobile construction machine, especially a mortar injection machine or compressed air generator, has a propulsion engine installed in an engine compartment (32), a bottom cover fixed on a chassis (10) and closing off the engine at the bottom, and a fuel tank (36) formed as a plastic injected component. The fuel tank forms at the same time the bottom cover. The fuel tank has the design of a double-walled floor pan closing off the engine compartment at the bottom and provided with a cavity, accessible through a filler neck, to hold fuel.