Slick Magneto Problem - Rave to Eric Muelburg!

[Tankerpilot75]

I want to express my sincere appreciation to Eric Muelburg for diagnosing and then fixing a left magneto problem on my RV7A. Eric is an EAA Chapter 24 Tech Counselor and an A&P. He also volunteers every year at Air Venture.

Several weeks ago during a run up check prior to takeoff my engine really coughed hard and acted like it wanted to die when I did the mag check on the left mag. Having had past trouble with plug fouling I taxied back to the hanger and cleaned my plugs. The next time I went to fly it did the same thing so I thought that my left mag had probably failed and called for help since this is an area beyond my normal comfort level.

Eric spent the whole day with me doing a number diagnostic steps and discovered the 7/8? condenser nut on the ground pole of my left Slick mag was loose. This loose nut allowed the mag to ground out with the p-lead connected. It obviously started out as an intermittent problem but progressed to total mag failure over time. He tightened the condenser nut, did some more diagnostic steps to confirm the problem was fixed, and then re-timed the mags. Total cost - lunch on me!

While I can?t say for sure this problem has been causing my plug fouling, I do believe it has been going on longer than I knew. Mag checks are important - do not gloss over them thinking you just have a fouled plug or two that will clear up with a little use. We were both happy a simple fix was all that was required.

It?s people like Eric and the EAA community that make owning and flying experimental aircraft such a wonderful experience. Thank you Eric.

[Ivan Kristensen]

In 1050 hours of flying my RV-10 I have had two Slick Mag failures. the first one was a total failure returning from Oshkosh in 2014 at about 700 hrs TT. the second one, a partial failure, was last week returning from Florida to home base with only 368 hrs on a new mag.

My set-up is one Slick Impulse Magneto firing the bottom plugs and a Light Speed EI firing the top plugs. Both my failures happen during cruise flight and were barely perceptible. The only way I could tell was that leaning to LOP was giving me erratic indications and a slightly rough running engine. Running it ROP it ran fine.

In the case of the first failure I didn't even know what had happen until the next day when I went to do a run-up, when I switched off the EI the engine almost quit indicating a dead magneto.

The second failure last week the indications in the cockpit were the same but after I landed and did a Mag check the engine would still run on the MAG only but very rough.

My mechanic next door was able to repair it. He found that the secondary coil had gone bad plus the plastic cam was worn and loose. It is back on the airplane and working great once again.

The issue here is what is going on with Slick Magnetos? I am told that the quality of Slick is not what it used to be and have been going downhill over time and that a Bendix magneto is a better choice. Is this consistent with the findings of the readers of this forum?