what are the specs of this outrigger? That motor may not be too big if you know how to set up a rigger right. What esc are you going to use that may give us an idea on lipos or nimh's. Also if you run lipo's, mabey you could run one 3s pack, so your motor will have time to cool down. It is like running a car motor 24 hours straight with no load on the engine, it will eventullay poop out ethier your batteries, esc, or motor.
Dan