Bones,

That is diffinitly a one piece muffler that looks like it had been press fitted together. I do not think you can take it apart. I would call Horizon Hobby and talk to their tech support and they my just send you another muffler. The muffler issue is why I choose to buy a OS GT15 gas engine. With the specials Tower is running right now I got it for 299.00 delivered. I have an NGH GT17 and have been fighting muffler issues with it for 6 months and did not want another engine that had these issues. Good luck with it and I think Horizon can help you. They have really good customer service.

Jeff,

Nice looking 4 Star 60. That plane is a great fly plane. I have the 4 star 120 with a DLE 20 and it is my beat flying plane. The Evolution 15GX should be a very good fit for your 4 Star 60