Rotax 582 with large EGT and CHT differential

[j_omega]

I have a brand new Rotax 582 that I have been test flying. The PTO cylinder is running good temps (220 CHT / 1050 EGT). However, the mag cylinder is running a low CHT (190) with a high EGT (1150). This would seem to indicate incomplete combustion in this chamber. I have verified the carb sync several times now, tried swapping carbs, verified the torque on the head bolts and spark plugs, and even swapped sensors. Starting to run out of ideas now. It concerns me a little that the problematic cylinder is the side on which I installed the oil injection tank.

[avidflyer]

Usually people only run coolant temperature gauge on the 582. Have you tried swapping the rubber carb boots? Possibly you have an air leak somewhere on the hotter cylinder and carb boots can develop cracks or leaks. That of course would lead to higher EGT temps. Does a visual inspection of the spark plugs verify that your EGTs are higher on the one cylinder then the other? Location of the oil injection tank should not effect one cylinder more then the other. Just to be sure, the oil tank you are referring to is not the small oil tank attached to the side of the engine above the carbs is it? That little tank holds an ounce or two of oil, an oil injection tank usually holds about a gallon or close to that. As far as incomplete combustion, that would lead to lower EGTs, not higher ones. A 2 stroke engine is run intentionally rich in order to keep EGT temps low enough to keep the motor from cooking it's self. Of course if it's run to rich it will choke it's self, but there is a sweet spot where it makes good power, and still keeps it's self cool enough to survive. JImChuk

[109JB]

Did you check the carb jetting and the clip position on the slide needle?