Ok, ill give both of them a try. I don't think its a nipple, because I put a new nipple in it when I got it. Wait, do you think the nipple isn't big enough? I mean opening wise. Maybe I need a bigger opening nipple. It was broken off when I got the engine, and the lhs gave me a replacement, I believe a dubro. I drilled the size the directions told me, and threaded it in. Wonder if I got the wrong size. I'll check into that. And try to reposition the muffler, and pull the carb off and look at the cats eye. Thanks for the help. If everythings ok, I'm gonna go the hi temp sealer route. I'll let you know how it comes out.