markkahn Posted May 13, 2021 Report Share Posted May 13, 2021 I haven't flown my plane in a few weeks, got in it today and it was idling at ~1600rpm instead of ~1900 like normal, and was climbing at 5,200 vs 5,500 normal, and 5,400 cruise at full power vs 5,700 normal. Just looking for ideas of what to check for, as the engine sounds and feels perfect, it's just seems like the throttle was physically pulled back a bit, and I'm confused. It's a Rotax 912uls Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted May 13, 2021 Report Share Posted May 13, 2021 What airframe? Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted May 13, 2021 Report Share Posted May 13, 2021 Generally air, spark or fuel. * Have you changed (or cleaned if K&N) air filter within a reasonable interval? * Check air path and make sure you don't have a kinked/crushed SCEET tube or other air obstruction, tube off the airbox, or split that is leaking air. This one's pretty unlikely as the engine would be feeding air differently to each carb and make it run rougher, but it's good to check. * When was the last time the plugs were changed? If you pull them, just replace them -- they're cheap (unless you have the new style plugs). Check gaps and coloration. I use a 0.025" gap, they will open up a bit to 0.027-0.028" over time. If they look bleached or dark you are running too lean/rich respectively. They should be the color of coffee with cream in it. The bottom plugs in each cylinder might be slightly darker as some oil/fuel can collect on them. * Check plug wires to make sure they are tight on the plugs, no split boots or damaged plug wires. * Check fuel flow at the gascolator, make sure the fuel is dumping out quickly enough to feed the engine. If you have an EMS, check fuel flow and pressure numbers. * Check the weight of floats in the carb bowls, if they are heavy the fuel level in the bowl will be high and can over-richen the mixture. * Check throttle cables, The throttle lever should hit the stop, and the throttle cables should hit the stops on both carbs at the exact same point. Lastly...has the prop pitch changed at all? Quote Link to comment Share on other sites More sharing options...
markkahn Posted May 13, 2021 Author Report Share Posted May 13, 2021 @FlyingMonkey -- Your post should just be sent out to every owner, thanks so much! Quote Link to comment Share on other sites More sharing options...
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