Just me Bill, but I don't use thread locking goop on an engine unless I need it and so far I haven't. But I only use four strokes that have a different muffler mounting set up than two strokes. And far anything as any thread locking compound marked as "Permanent" for two stroke muffler mounting, I wouldn't use it. Steel screws going into aluminum, thermal coefficient's, not good. Your better off using an anti seize compound with the proper torque applied than using a thread locking compound.