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
to recommend against buying this engine, unless you plan on getting it only as a core. Rotax has made many running changes to these engines over the years. Some of the changes are mandatory; some are merely improvements. They cover everything from oil dipsticks to rocker arms to coolant tank cap pressure. You certainly can check, using the Rotax Line Manual, but the best way to be sure everything is up to date is to see that routine work was done regularly at a Rotax Service Center. Here are a few tips about how to recognize updated parts: The cad-plated starters are newer, have higher torque, and are recommended for any 912S. The black-top carbs are newer than the cast ones. Square-top dipsticks are mandatory. Rotax increasingly recommends use of safety wire. It won't hurt to safety everything that could conceivably work loose or fall off. Proper location of the oil tank is critical. Each installation is unique. On this Powrachute, locating the tank is simplifed, since the powered parachute does not go through radical pitch or roll changes. Fuel and oil lines that aren't properly routed or secured can cause trouble. Though of course you'll do it right, if the seller didn't, he may have done other things wrong, too. Paskevich said, "If a guy's taking shortcuts, you wonder what he's doing on the more complex or more expensive tasks. And look at the airframe logs; you may find things there that aren't in the engine logbook. You may find 'interesting' entries and gain some idea of how the engine has been used. Maybe you'll find a prop replacement. Was there a prop strike?" Keep in mind that most airplane engines in noncommercial use will rust or corrode to death long before they reach TBO. Frequent flying, with thorough and routine maintenance, is the best engine life extender. A look through the logs helps ask the right questions. Steve Swif's Kolb installation demonstrates proper orientation of lines— plenty of space. Disconnect the ignition and turn the engine over by hand to feel for any "flat" cylinders. Sitting for an extended time can allow the hydraulic lifters to drain, and once they do, they rarely pump back up. It may not be the lifters, either. You may get lucky; you may not. Additional Paskevich advice: "Look at the prop. Is it damaged, chipped, repaired? Has it been dynamically balanced?" The gearbox's magnetic plug may tell you something useful. Look. If it was cleaned, say, 50 hours ago and now it's covered with metal, that's not good. "If you can get access, look at a cam lobe. (You'll have to pull a cylinder.) I've paid to partially disassemble an engine, and it's the best money I've ever spent. You'll want a qualified tech to look, if you can get a compliant owner. Maybe you'll spend a few hundred bucks; that's better than a $10,000 parts bill, later. If the paperwork is poor, you'll want to do this." If the logs are incomplete or don't look right and Photography by Tim Kern A cooler this close to the mufer won't cool very well and may encounter interference in operation. In cold climates, it's better to incorporate an oil thermostat (Varitherm) in the system. EAA Experimenter 35