Hi Ty, the answer is yes mate, you could convert it, (electric to petrol) but you would need the following:
(1) new engine shaft
(2) Cutter clutch assembly complete
(3) new chassis with the clutch lever assembly complete
(4) suitable horizontal shaft petrol engine with throttle control.
The best method would be to grab a second hand petrol machine and christmas tree the bits you need to make one good petrol machine!