The fuel tank, lines, and any pump you use must be "Gasoline compatible". The hobby shops sell gasoline pumps, and conversion kits for the fuel tank. The stopper in the fuel tank must be changed, and the kit includes the stopper.

Here's a thread with info on fuel lines: http://www.rcuniverse.com/forum/m_6026041/tm.htm

Have fun,
AV8TOR