Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.
Issue link: http://experimenter.epubxp.com/i/118927
Un d e r t h e C o w l Although Rotax approves the occasional use of 100LL, a steady diet will build up deposits like these. Buying a Used Rotax Four-Stroke Engine What you need to know By Tim Kern With a quarter century of history now behind the Rotax 912 series engine, it's time for a primer on what to look for when one enters the potentially dark world of used engines. Although all the usual used engine caveats pertain (see Experimenter, March 2013, page 36), there are some Rotax specifics, as well. The series has three basic models: the original 80-hp 912, the 100-hp 912S, and the 115-hp turbocharged 914. The fuel-injected 912iS was introduced in 2012 for original equipment manufacturer (OEM) use only; it's unlikely you'll be buying a used one out of an airframe anytime soon. The 914 is a lower-compression 80-hp 912 with a turbo. In this article, we'll ignore the turbo; turbocharger inspection is best left to a qualified shop. Such high-output, high-rpm, small displacement engines are mated to gearboxes that make this formula work. The Rotax is happy cruising at 5,000 rpm; a sure way to destroy it is to "lug along" at 3,800. The gearboxes, too, have their demands and personalities. All Rotax units are designed for long life and reliable operation, but they are distinctly intolerant of misuse, clumsy operation, or neglect. Photography by Tim Kern Your First Look As with any used engine, the history, especially the recent history of the engine, is a big deal. How recently was it flying? How was it stored since then? Mark Paskevich, president/ owner of Rotech Research Canada Ltd., the factory-authorized North American distributor for Rotax aircraft engines, said, "The most important thing is the pedigree. What documentation can you find? What's the level of compliance with Rotax service bulletins and airworthiness directives? Go through the logbook, see how meticulous service was, and note who did it." Rotech's website, www.Rotax-Owner.com is a comprehensive and free website. Register and enter the serial number of your engine, then print all the updates. Cross-reference your engine's documentation with those documents, and see if your engine is in compliance. Ideally, you'll see the engine on the airframe. If this is a homebuilt, how "factory" is the installation? Is the oil cooler mounted correctly (with the outlet fitting at the top); are other lines connected to the appropriate outlets—forward or rear—on the engine? Is the oil tank installed so that it keeps the oil level between the inlet of the oil pump and the EAA Experimenter 33