Doug Michael took very good care of this engine, and never had a problem with it other than the oil injection would not pump the correct mixture to the engine. He purchased a new pump, new lines, new filters, etc. The injection system was running at 120:1. Blocking the pump lever full on would only give 70:1 and he and I both carefully checked oil consumption over time, but could get no better results.
Doug thinks that when the engine was new it did inject more oil, but we could never find the problem. Doug removed the injection system, and began mixing his fuel at 50:1 At about 650 hours he thought he would give a Hirth a try, and sold his old engine, gearbox, and prop to me.
I took the engine apart to be sure it was not damaged and was clean and assembled correctly before installing it on my Chinook. I now have added another 300 hours on this engine, and continue to mix at 50:1
.( Doug now has a "blue head" Rotax 582 on his plane)
Heating the screw, allowed me to remove it.
I am told that Rotax plugged this hole because owners would complain if they saw any antifreeze leaking from joint between the case halves. With the hole plugged, any coolant that gets past the seal has no place to go, but into the rotary valve oil. This is a common problem with the older 582 engine that uses just a lip seal for the waterpump.