This system and motor are being used in a homebuilt airplane that also has a turbo added. We think the issue (mid RPM surging) is O2 related, but not 100% sure. The exhaust had to be shortened for use in the airplane of course and modded for the turbo, but the problem is the rpms surge at part throttle. The OEM O2 sensor is the basic on/off style but it works backwards to most. I doubt it needs the sensor heater, but wonder if maybe a wide range sensor would cure the problem. This is about the last thing needed to make it run right for flying.
The laptop reads it as running too rich. Any ideas?