It took me five sessions spread across three weeks to accomplish the purging of the oil system. Basically I followed the Installation Manual chapter 79-00-00, supplemented by the Service Instruction SI-912-018. I also viewed a few YouTube and Rotax videos, which in some cases offered useful info and some cases not. Four things set me back: for a while I did not have the Dynon Skyview EFIS set up so did not have an oil pressure reading, a hose fitting on the oil pump was not correct causing a leak, I did not have the correct pressure sensor on the oil pump and I had to gather the extra equipment to perform the purge. So, in parallel I got the Dynon going, ordered the correct fitting (Rotax part 956641 instead of 956577) and swapped out the pressure sensor. For the extra equipment I borrowed the flying club's air compressor, rummaged around in my odds and ends boxes for some hose pieces and fittings, and bought one or two other fittings at the local plumbing shop. I was concerned about applying air pressure to the oil tank as one bar is at the very low end of the compressors scale. I was careful with the out going regulator on the compressor and used a valve in the air line to let in just a bit of pressure at a time, periodically re-charging it during the purge. Once all was set the purging went very smoothly. It took about 30 revolutions of the prop by hand to get a pressure of about 30 psi on the Dynon screen oil pressure guage. No oil passed through to the temporary jug hanging off the disconnected oil return line.
