Just an FYI but there is a glow engine forum and you can ask the service rep directly, in the case of OS that is Bill Baxter. You have to give him every little piece of information though so he has a good idea of what is going on with your engine. I must have missed it in one of the posts but this is the first I have read anything about a loose carb screw or a thread problem. One friend with a .55AX had his carb come loose, both screws fell out. He didn't notice it for a while, he was fighting the engine all day. He replaced the two screws with something he had at home and the engine was still running for crap. I just happened to have two factory screws from OS in my box and he replaced the screws with the correct size and length then the engine ran fine again. The ones he was using were just a little longer then the correct ones. Just something that simple cured a bunch of problems. You should really go ask Bax and see what he has to say. Leave no information out when asking him so he has a clear picture of what you may have going wrong. If I have a mystery problem Bill is who I ask for help. Most the time he is correct or helpful, it's hard to figure everything out without having the engine in hand so Bill isn't always 100% correct but he is usually more correct then not. Even if his answer doesn't fix my problem it points me into another direction I haven't thought of. Give Bill a try, it's better to ask someone who sees these engines day in and day out and has a better understanding of what can go wrong.