While I hate to say foolproof........if you want to decarbon an engine, just warm it up and pour in a pop can full of water. Very slowly, so that the engine won't quit. I saw it the first time when a friend was about to overhaul a 350 Chevy in a van. This is a bad idea if you have a catlyst monolith in the exhaust. It will fill with crap. He dumped two cans into an engine with 150,000 miles on it. When he took the heads off they look as though they had been bead blasted. even the intake valves were clean.

The Idea that a rotary can ingest any foreign material should be drivin from your brain. I lost one from a flake comming off of a carbon apex seal. A friend lost one to a scrap of safety wire less than 1/4" long. It is not the mechanical damage that the material can do. It is the ability to damage a seal groove and stick an apex seal deep in the groove and then the burning fuel air mixture from one chamber lights the one behind it (and that in the inlet tract) and brings the rotor almost to a stop from high speed. It will keep doing this until you shut it off or it breaks a stationary gear. Never ever run one without an air filter in place.
Lynn E. Hanover.

I totally agree with you Lynn, I think the reciprocating wiping action of a piston tends to wipe away foreign material, but the rotary does not go back and forth it stays in there.  Might be why they seem to be more sensitive to dirty oil than piston engines.

Hans

 
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