Mep003's take internal or external fuel sources.
You can check in the manual to see how to run externally.
The short story is there is a "Prime and Run Aux" swithch for auxillary fuel, and a "Prime and Run" switch for internal fuel. So after priming from the aux switch, then hitting the start switch to run, revert back to the "Prime and Run aux" switch rather than the "Prime and run" switch. That will keep your auxillary fuel pump running and sucking the fuel out of your aux. tank. You mght also need an external pump to go in your aux tank or 55 gal drum, depending on how long the hose run is, elevation, etc.