Stator(s)..... The early model stators did not have any molded insulation surrounding them, rather the coils were not insulated and were quite visible. The later model stators, including todays models, have a molded insulation material surrounding the coils.
In either case, there are a series of small coils on each side that provide AC voltage to a rectifier that converts that voltage to DC voltage to charge the battery. There are also two larger black coils at the rear of the stator that provide approximately 300 AC volts to the powerpack capacitor which is needed to engage the ignition.
Whether the stator is insulated or not, visually inspect the stator to see if it is cracked and especially to see if one or both of those two large black coils might be dripping a sticky looking substance down upon the powerhead area (meltdown). If a meltdown exists, replace the stator as that condition results in a AC voltage drop to the powerpack.
Although the carburetors have been recently rebuilt, there is always the possibility that a bit of foreign debris may have broken loose and has found its way into the high speed jet area... that would knock out one cylinder at the higher rpm setting.
NOTE: DO NOT run the engine at full throttle when out of the water as you are risking a runaway engine situation.... the engine diesels and keeps increasing its rpms. Should this occur, by the time you figure out how to shut the engine down, connecting rods could be flying out the side of the crankcase.
Out of the water.... the engine is not opening up, it just seems that way. There is no exhaust back pressure to hold the rpms down. The engine could be running on half the cylinders and stilll scream away.
