Rotax 503 rpm drop
in 2 Stroke Technical Questions
6 years ago
I have a 503 engine on a powered parachute. Had an unexpected (obviously) water landing and aircraft was underwater for couple of hours. After getting it out took carbs and exhaust system off and took engine to Rotax certified mechanic who completely disassembled engine to clean out dirt, rust, and corrosion. I disassembled carbs and fuel pump and cleaned them out twice. New plugs after reassembling everything. Bled auto oiler system, and fuel and oil seemed to flow just fine. Set prop pitch to 10.5, warmed up engine, and then ran up engine. Around 3700 to 4000 rpm would drop back to around 3000. Then RPM's would surge forward to 6000 if I continued giving it gas. Cut back throttle immediately. Reset pitch to 10.5 and it did the same, this time starting around 4000. Does anyone have any ideas about what might be wrong.?
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