Re: Help.. Broken Bottom engine casing.
If you think (or know) you put straight oil in the tank, or aren't sure what mix is there now, I would drain the tank, line and carb and start fresh with a new mixed batch. We have had a couple members pour oil into the tank at gas stations to mix their fuel that way, and they end up with the oil going straight into the carb.
Any doubt? Throw it out. (properly, like mixing it with straight gas and using it in a lawn mower.)
The grey gasket maker will work fine BTW.