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I had a rough running engine. I tested the primary ignition according to the service bulletin and found I needed to replace the ignition modules. So I just replaced them and now the primary ignition switch shuts off the ignition. I went to check the ignitions to see how close the rpm's are. What I have is as follows. 1600 rpm for both on. 1525 primary on and secondary off. 1530 primary off and secondary on. I retarded the secondary and the secondary was further off and advanced it to what I have now. I am wondering if I may have a bad plug/s? My EGT's and CHT have always been under the maximum allowable. Everything was well tuned prior to the last flight that the engine started running rough. Any suggestions? I did send a note to sonex.

Check plugs and ignition wires. Before that check the drop at 1900 rpm and see if it is less pronounced. AT 1900 I see about 35 to 50 rpm drop with primary only and 50 to 70 on electronic only.

I used to do my mag checks at 2000 rpm at least. Also, lean the mixture to get a smooth running engine before doing the mag checks.

Not sure if this is relevant, but I recently learned a lot reading Mike Busch's articles on this kind of thing:

http://a.moirier.free.fr/Pilotage/Au%20sol/The%20mag%20check.pdf

https://www.savvymx.com/index.php/articles The EGT myths debunked was good too.

Mike is there a secret to getting into Busch's articles? When I clicked on (http://sonexbuilders.us8.list-manage.co ... cb603f39e7) it sent me to a page with a series of articles but when I clicked on one of the articles It sent me to never-never land.

Jim1342 wrote:Mike is there a secret to getting into Busch's articles? When I clicked on (http://sonexbuilders.us8.list-manage.co ... cb603f39e7) it sent me to a page with a series of articles but when I clicked on one of the articles It sent me to never-never land.

Yeah that list is just a list and not a link to the actual article. The best way is to go here and look at the Sport Aviation Archive http://www.eaa.org/en/eaa/aviation-education-and-resources

I have not posted the results of my ignition. I sent the magnate one back to Sonex and mine were defective. They would spark but could not be shut off. I replaced the magnetrons and test ran the engine. At the lower rpm there was a wide rpm difference. I re tested at 2000 rpm and had little change. Then test flew the plane for a couple of hours and did the airborne test per the Aerovee manual and the CHT's were with in a few degrees. I also found a ground from the engine block to the FW ground block loose. That was fixed before the test flight. So now the engine is running great.

Glad to hear it's running smooth again. Did you loctite the grounding cable so it won't happen again?

It was a bad crimp. I fixed it and ordered a new factory made cable from B & C. That was my plan from the start but I never got around to ordering it.