airwalk
02-08-2006, 09:40 AM
I have recently put a jr ergo back in the air running an os37. Last I flew it was back in Nov and engine was running fine. Ambient temp then was average high 20's. At the moment ave temp is around 35c. I have a new plug and fresh batch of fuel. Cool power (red) 22%, Nitro 15%. The problem I am experiencing is hovering for about first 3-5 mins ok then tried a climb out and settled back to hover engine changes sound/note (I can only describe it as a crackling) Landed and cut engine while I made some tail adjustments, fired it back up and brought to a hover and after a short while the engine changed from a smooth sound back to a crackling sound. It doesnt seem to affect the performance and appears to occur when it gets the temp up. I have a good steady stream of exhaust. Could this be the idle mixture too lean? Or maybe not quite rich enough on the main, although there is ample smoke streaming. Appears to have plenty of power in climb out without bogging down.