Due to the walbero carburettor's not having a linear throttle response set servo to carburettor linkage with full mechanical expo as per Malorie’s gasser throttle linkage setup. This achieves the best throttle performance & response.
In brief set servo arm with mechanical expo so that at full closed throttle it is pointing nearly straight down the linkage and at full throttle it is pointing just past 90 degrees. The arm on the carburettor should be positioned so that at full closed it is at nearly 90 degrees and at full open it is pointing almost straight down the linkage.
Photo from runryder
Engine throttle surges
If you have signs of significant throttle surge, turn off the governor & fly on throttle curves. If the surging has disappeared it is not a carb/fuel system problem but related to the electronic throttle control (governor).
1) Is your Governor compatible with gasser use? Clarify with manufacture.
2) Is it reading a strong sensor signal.
3) If so reset your governor to default & redo your parameters specifically to function with gasser parameters.
4) If the problem still persists move the location of the governor in relationship to other electronic components. IRF can affect the operation of the governor.
5) Still no change then try swapping out both the sensor & then the governor one by one with a replacement. I have experienced failures with both new & used equipment.
Second hand items could have the appearance of being hardly used but may have been involved in an extremely hard hit. Usually the sensor that comes with your governor can be used without a problem. If the sensor is magnetic it may be fixed to your flywheel housing on the exhaust side of your engine for an adequate sensor reading or mounted on the frames if using the lynx clutch.