[QUOTE=navygm;9927990]
I dont really like Rotax mainly for how they work... when its started its like a farm trucktor working a field
Even when you shut down, that stiff movement it does to stop, comparing to a sort of smooth stop of Cessna or other US made aircraft, makes me worry what stress is being created on the gearbox and clutch. But that could be my perseption, so I might be wrong, Im not an engine expert.
QUOTE]
As someone has already mentioned, the harsh start of the 912ULS 100hp can be overcome by having "soft start" ignition modules, the bigger starter motor, good battery and keeping the carburettors well balanced with each other.
A soft shutdown is achieved by ensuring that the hot engine idle is set at 1400 rpm, turning off one ignition circuit and waiting several seconds until the engine either dies of its own accord, or switching off the other ignition.
Unlike the totally air cooled Lycosaurus engines, the Rotax 900 series have water cooled heads which make them "bomb-proof" against shock cooling, a common reason for cracked heads.
I've flown over a thousand hours with Rotax 912UL 80hp and the 912ULS, finding them both reliable, economical and offering a great power to weight advantage. They use about a thimbleful of oil per hour and are simple enough to work on. It's not for nothing that the majority of new light aircraft designs use these engines, which easily make their 2000hr TBO if well-maintained.