Here's one that's causing me grief. Has anyone else encountered this before?:
Shortly after starting the engine the voltmeter indicates at 16v, (higher with higher RPM - meter pegged at limit, showing at least 18v @ 3000 RPM). The ampmeter similtaneously draws -8 to -10 amps (altho the amp meter may be wired in reverse, because is always reads negative 1-2 amps when all else is normal).The overvoltage reading lasts 3-4 minutes then returns to normal readings (14 v, -1A) & doesn't re-occur (or rarely re-occurs) for the rest of the flight.
There is no smoke or electrical burning smell. This happens even if the engine was recently started (still warm, no moisture, battery fully charged). Sometimes it happens after T/O. Turning off the Master switch sometimes helps bring it back to normal faster, but not
always. Placing a greater voltage demand (ie., selecting the gear retraction switch to up momentarily (amphibious floats), turning on the lights, etc..) brings down the voltage somewhat, but not back
down to normal (14v). When the voltmeter is pegged at 16v+, sometimes the Master switch does not turn off the current (it should, but it's as if there's a temporary short).
I realize that the battery gets drained a bit to crank the engine, but the engine always starts quickly (1st try), so the draw is small. The battery seems to charge well when the engine runs (-1A), and seems to keep its charge.

Some have suggested that a bad ground to the rectifier-regulator could be at fault. I cleaned & tightened that ground and any others I could find, to no avail. I checked for loose wire connections and burnt (brownish/discoloration) wire insulation but cant't find any. I read the Rotax installation manual (Sep 1989) which addresses the possible reasons
for the failure of the rectifier-regulator (pg 22 in my manual) but being a "Buy & Fly" kinda guy, the "non-obvious" stuff is Chinese to me. Others have suggested that the rectifier-regulator could be at fault, which I don't mind replacing if it'll fix the problem, but at $170, I'd like to check everything I can first. Any ideas?
Thanks for any help.