ORIGINAL: Gray Beard
ORIGINAL: ohnoucdat
Marvel mystery oil has a cutting agent in it. I know several will say I've used it for years, but its a fact that it contains a cutting agent. Marvel does make an air tool oil that is great for after run oil. This question pops up ever so often. I use it regularly, run my engine dry after flying day ends,and drop a few drops in the carb,on 4ST's I flip and run some in the vent tube,turning the prop so engine will ingest it. Like was said earlier cheap insurance. I've read and heard that putting it in threw carb,can damage o-ring gasket,but never had a problem, just like some may not have a problem with marvel in there engines.
You don't want to use any petroleum products in A YS engine because it will destroy some little things like the diaphragm. The instructions state this but people still do it and wonder why there engine quits running after a while. I haven't seen any of the oils used as an after run harm the silicone O-rings in any glow engines but it seems others have?
I would agree with that, never owned a YS or a pumped engine,but that makes very good sense not to use it in those engines.