Mooneyboy,
Jabiru engines aren't necessarily unreliable. The more recent versions seem to be relatively trouble-free. However they seem to last about half as long as Rotax 4 strokes before needing a thorough overhaul. But being air cooled makes them lighter than the water cooled Rotax types. As with the larger American engines like Lycoming, the Jabirus are more prone to problems arising from shock cooling of the cylinder heads when fully closing the throttle for a prolonged descent.
Jabiru reliability and life seem to lie somewhere between that of the excellent and remarkably reliable Rotax 582 water cooled 2 stroke and the very widely used Rotax 912 series 4 strokes ( over 90% of new designed small SEP types use a 912 with good reason ) which makes the Jabiru a very acceptable power unit. The uncertified Rotax 912 types can go beyond 2000 hours TBO, on condition in permit aircraft.
A good idea to Google for history. I've been a commercial pilot for decades and done private flying behind all the above engines. Friends also seem happy with them.
Last edited by Colibri49; 4th Aug 2016 at 11:00.