Portable Air Compressor not starting

Dewar sir, Our atlas copco compressor has not being in use for three years. Two weeks ago we kicked it, it started only after removing water that had found its way into the engine/piston.We loaded air, allowed it to run for a few minutes. We repeated this about five times before shutting it down. We returned yesterday but the engine wouldn't start. The technician concluded that its the rotary screw head tga is responsible (after extensive checks on the engine).  Can this be true? What could have caused this? What is the solution/way forward. Thank you