Sorry, that's nonsense. He probably should replace the plug but that kind of blanket condemnation doesn't wash. I have engines that run great with a Fox long with an idle bar.

His problem is probably with junk in the carb. It could clear itself or he should pull the carb and clean it. Check for loose screws and cracked gaskets or o'rings. No reason it shouldn't run as good as it did when you stored it.