Downhill From Here?

On Friday November 11th N50KB had its first engine run.[KGVID][/KGVID]A visit was scheduled with a FAA FSDO inspector for the afternoon of Wednesday the 22nd.  In the interim I completed wiring and testing the Pilot and PAX seat heaters; and sealed seven more firewall penetrations with red high temperature silicone caulk.

Wednesday morning I started the engine with the intention of taxiing to check the brakes.  It ran rough and was shut down.  The #4 cylinder was cold. Inspection showed valve movement was OK and another start was made.  The engine again ran rough for less than a minute and was shut down.  Instruments (Garmin G3X) showed the #4 CHT and EGT rose only to 150 and 205 degrees while the other cylinder temperatures appeared normal. An overly lean condition was suspected.  The #4 fuel injection restrictor was inspected and blown clean with air.

The FSDO inspector arrived and was told of the day’s activity.  I agreed to a suggestion we do an engine start.  During the start sequence the #4 EGT was seen to rise rapidly and then decline.  Other cylinder temperatures were normal.  The airworthiness inspection was terminated.  During post run discussion a fuel flow test and plug sparking test were suggested.

Fuel Flow Test

The fuel distribution test collected avgas from the four injector lines while the fuel boost pump was running.  This photo shows the results.

Fuel Flow Test Result

From left to right the cups contain the fuel for cylinders 1,2,3 and 4.  The overly lean condition of cylinder #4 is obvious.  There was likely a problem in the AVstat fuel distributor on the top of the engine.

Plug Sparking Test

The plugs were removed and their cases connected to engine ground by safety wire.  With the master and ignition switches on, the propeller was rotated by hand.  Sparks were observed from the plugs connected to the left E-MAG.  The plugs connected to the right E-MAG did not spark.

Brad at E-MAG Ignitions was contacted by phone.  He led us through several levels of tests that at end indicated the right E-MAG was operating OK.  He then asked me to remove the right E-MAG.  I was to verify the magneto shaft is engaging the drive gear in the engine accessory case.

I removed the E-MAG.  It’s shaft and gear look OK.  I then reached into the accessory case to feel the drive gear.  This is what my fingers found. A broken magneto drive gear in a factory new Lycoming YIO-360-M1B engine that ran a total of less than 1.1 hours, with over an hour of that time on the factory dynamometer.

Broken Section of Magneto Drive Gear

The following Monday began  a week of phone calls and emails with several levels of the Lycoming warranty organization.   Dolly had returned to Florida and before driving south I proceeded to pickle the engine with fogging oil and desiccator plugs for the winter.

Eventually Lycoming agreed to send a packing crate and pay to airfreight the engine back to the factory.  Dolly and I drove back to Michigan where I spent several days removing the engine from the plane and with help from friends preparing the shipment.  I took many photos of the process.  The engine arrived in Williamsport, PA on January 2nd.

Ready to Ship


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