Need help with Tachometer Error

[FoxDB]

I have a 582 in my Kitfox with a Westach Quad gauge. The last 2 flights are showing an RPM drop of 1000 on one mag but only about 100 on the other mag, yet I can tell by the sound the drop is about the same. There is only one tach lead from the engine so I don't know how it could be the tach. I am wondering if there is a flaw in the ignition/electrical system that would cause this. Any help would be appreciated.

[DesertFox4]

FoxDB- I'm bumping this so it gets visibility again. I'm not a 2-stroke engine guy so hopefully someone that is will see this post and assist.

[t j]

FoxDB,
There is a thread on the rotax owner site about this. Seems it happens at times. Near the last of the posts there is one guy who has fixed his. The fix isn't easy so most people don't pay attention to the tach and just listen for the proper change in engine sound for the mag check.

Here's the link to that thread http://www.rotax-owner.com/forum/1-2-stroke-technical-questions/1064-magneto-drop

[FoxDB]

Thanks TJ,
This helps me not worry too much.