Identify this on Magnetic Plug

Hi Ried

My guess is that you might have chipped off a small piece of the spline on the prop shaft.  Sometimes the top spline where the keepers are might flake off a bit.  Only way to know is to send in the box and have an inspection done.  That particular area is under a lot of pressure as the box absorbs the torsional moments and bounces with the springs.  The load transfers to the spline the keepers are locked into.  Just a guess however.  if it is more than 1mm by 3mm then you should for sure take the gearbox off to find the problem.  Smaller than that it is unlikely to cause any issue.  All the return oil/air from the gearbox passes by the plug and its purpose is to trap small ferris parts like this if they come off.

it is possible that it came off the main spline under the overload clutch, let's hope that's not it.  Just as a reference you can see a badly worn one here for a reference.  

Cheers

Looks like it is part of the lock washer that holds the gear on the crankshaft.

I would not fly that engine until taking maintenance action and receiving professional analysis/advice.  I recommend you ground run the engine, drain the oil and filter (take a warm oil sample while draining the oil ) and send it to a lab (I recommend Blackstone but up to you) for analysis.  Call the lab and tell them what’s going on and send the photo to them as well.  Recheck the magnetic plug for any additional chips. Cut open the oil filter and examine it. Wait for the analysis report and follow their recommendations in the report (and the Rotax Maintenance Manual).  Good luck.