Miss fire

The mag switches are grounded back to the engine no I don’t have an oil temp warning light all steam gauges but I actually see a drop on AC voltage in the stator when it starts missing I have meters hooked to the stator leads. It’s in a rans s-7 so tube and fabric but everything goes back to engine and battery ground.

continued.......

Apologies: When the ignition switches are off, the ignition is 'hot' or running.
When they are on, it turns the ignition off, stopping the motor.
So that theory went out the window.

Having said that, rough running at 195'F then back to smooth at 190'F sounds almost like some sort of alarm point, with a 5' deadband.
Is there anything at your instrument panel that could be switching on and off automatically at these temps?

Just saw your response, above: you already answered my question.

Just copied this from another website:

"For the past 6-1/2 weeks my 37 hr total time 912ULS powered RANS Raven has forlornly sat in the hangar due to a persistent 350-400 RPM drop at 4000 RPM. 
I had become so frustrated that selling her off cheap was becoming a serious consideration….so was burning it. ?

Last Friday  I finally discovered and rectified the fault, tipped off by a Vans RV12is engine installation instruction. 

Cutting to the chase, one of the 4 ignition trigger coils’ air gap was 0.002” (0.05mm) below the minimum spec set by Rotax. Yep, about half the thickness of a human hair is the difference between a barely detectable mag drop and one that made the engine rattle and shake….and it was clearly set that way in the Rotax factory.

The specified air gap range is 0.012” to 0.016”. My gaps were 1 x 0.016”, 2 x 0.012” and 1 x 0.010”….The problem trigger coil was the 0.010” gap.

(I had previously thought that closer trigger coil gaps were always better, provided there was no actual contact. Those with electronic expertise may be able to explain why that is not necessarily the case….?)
I now have 4 x0.014” gaps (actually 5 counting the tacho) and a very smooth running engine. 

So if you’re suffering a mag drop in the 300-400 RPM range on a Rotax, buy yourself a set of brass feeler gauges and check the trigger coil air gaps"

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I realise it's not exactly what you've got, but it seems out of spec trigger gaps can give you odd results, both over and under (the under is a bit of a surprise). So, something to check, I guess. It was followed by a discussion on where to find brass feeler gauges: many steel sets also have a brass selection in them. And check what gap setting is right for your engine: there is an old and a new type of trigger coil assembly, and the gaps are different.

No everything is steam gauges no monitors at all. I was going to check the air gap on the trigger coils but that still doesn’t make any reason why there is a drop in voltage at that temp from 30 to 15 volts AC when the charging coils for the battery are not affected.