Iused to fly about 10 years ago. Recently getting back into flying and purchased two Evoloution .52's. The first run on both of them did exaclty the same as follows: Started great and ran great however, the gasket between the muffler and the engine blew out, then the screws back out, causing the engine to die. Has anyone else had this problem and what might be the fix. Idid have locktite on them.</p>

If I remember correctly (day before yesterday) the 2 muffler bolts have split (locking) washers. That should be sufficient to secure the muffler. My gasket is long gone. Thinking that it's there only to accommodate for lousy machine work on the cylinder exhaust port and the muffler mount. Might run a stone across both faces to true them up for a better seal. I have had no muffler attachment problems - only dead sticks due to bad carb (replaced by Horizon Hobby at no cost).

CG - First, let me welcome you to RCU!

I get rid of the gasket and put a small amount of RTV on the muffler flange and that works well. When using the gasket, it has a tendency to expand and compress causing the nuts to vibrate loose. Just toss the gasket. Another trick is to re-tighten the muffler screws/nuts after the engine has been run and is still warm.

Best of luck with this great hobby!!

Loose the redundant gaskets

If your screws were loctited, they likely didn't vibrate loose but just wound up loose when the gasket compressed. There's nothing wrong with using a gasket, but you do have to understand that it will compress a bit in the first run or two. The remedy is to not loctite the bolts so that you can retighten them after the first run and again after a couple more runs.

Just do as seamus said and clean up the surfaces then do as Kaos said and run up your engine to operating temp. and then tighten up the screws. The heat of the engine expands the aluminum hotter then the steel screws so they tend to come loose. It's normal for pretty much all engines to loosen up the screws when new. Don't bother with the gasket. I have only one engine that I use the gasket on, the gasket is different then others and really keeps the exhaust from seaping from the muffler. I still tighten the screws when hot.