Picked up this 288xp the other day, started on 2-3 pulls idles great throttles to full power no problem. I took top cover off and noticed an aftermarket cylinder on their so I wanted to check it out before selling. I pulled the muffler and it looks like previous owner put in (2) thin rings instead of one thick ring like it's supposed to have. Is this something any of you experts have seen?? Any info would be much appreciated.