Originally posted by MikeSell
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I buy norvels because they are light, quiet, fuel efficent, inexpensive, durable, reliable, powerful, and fit in almost no room whatsoever. Their mufflers are lacking in the way they seal. 
Ditto
Norvel engines make 1/2A fun again. No more Cox for me.
I use the copper hi-temp silicone to seal my muffler. That is the only problem with these small enigines.