And back to the original question, i used regular silicone when reassembling the muffler after i read advise on here about doing so and it has worked fine since, now on my Magnum .52XLS it is spitting black goo all over my F-22 and it is because the center part of the muffler is loose and the nut it tightened all the way to the end of the threads, i will have to remove that one to silicone and add some washers to the bolt so i can get it tight.
On a side note i also have two of the .46 tower mufflers on my TT PRO.46's and i haven't touched them and they haven't came loose or spewed out the black goo.
As for the carb on my TH.75, on the test stand the carb barrel locking screw fell out during the second run, put back in and tightened it really good, has been fine since. The set screw on the throttle arm fell out on my second flight on a new plane, 10min WOT was not fun but the plane survived and the set screw was replaced with a machine screw with locktite, has been fine since. The LSN will slowly turn itself out when the engine runs, i tried a new o-ring but it still does it, i've heard that there might be a problem on the LSN that the groove might have been machined too deep, i've read a tip on using some dental floss to wrap around the groove before puttin the o-ring on, i will try this as this plane/engine has been out of commision for awile.

All in all this engine needed the most work out of my 12 2 stroke glow engines, but it does run quite well when you work out all the bugs.