Re: Spark Problem
I thought about the drop with an increase in rpm's and that is confusing to me also. The stator is basically an iron core coil, like a transformer, but only one coil. The magnet(s) embedded in the flywheel pass by these coils (stator/alternator) and as it passes it magnetically couples energy into the coils which either generates electricity or a trigger pulse.
If you are talking about the DVA voltage dropping, if you just took the DVA into account, the faster the pulses, the higher the voltage until it had charged up as far as possible and there was no more "droop" to the stored voltage therein. I don't see it an issue.
So, that translates to me as a stator output problem, or as far as triggers are concerned, an overloaded power supply possibly in the switch box.
I just went to the shop and got my manual. It is for later model higher hp engines so the wiring color coding is probably/appears to be different, but the theory is the same.
I noticed that the Stator output, includes outputs to the voltage regulator and other things. Of all the wires from the Stator, the only wires that are of the same color, (as your green wires are, and my yellow ones are) are the AC outputs to the rectifier, the output of which goes to the voltage regulator.
So.....before we go any farther since you said that the voltage from the green wires is 10-12v at idle and falls as rpm's increase I want to know:
Where are the other ends of the green wires connected (to what).....a rectifier bridge whereas the output goes to your voltage regulator....you may only have one module containing the rectifiers and regulator? If that is the case, the green wires will attach and red and black wires will exit with the black going to ground and the red going probably the starting solenoid hot, where the wire to the battery attaches.
If this is the problem, and "if" these suppositions are correct, your stator very well could be the culprit and it could be sucking down the battery voltage and reducing all the engine's voltages and hence the high voltage pulses to the spark plugs also, the higher you go in rpm's and would account for your poor performance and gooey plugs.
Stators, being magnetic devices usually fail whereupon moisture enters the wiring and shorts out a turn or more. Once that happens it's time for a new one.
Buttttt it could also be a problem with the rectifier or voltage regulator (if you have one).
Have you had problems with a discharged battery?
Measuring the voltage right at the battery terminals, what does it do when you increase rpm's? Does it drop? If yes, we are on the right track.
If yes, remove the green wires from whatever they are attached to and with them hanging freely in the air, attach your DMM's test leads and put the scale on AC volts, range 20V or so. Do the rev test and tell me what happens to the voltage. If it goes up, you probably have a module problem. If it still goes down then I would say that the stator needs replacing.
Get back with me.
Mark