The pictured case is different from an Echo 21.2cc. I think a different parent engine company.


w8ye: "Your goal is to have a static rpm of 7-8000"
I currently have 77-7900 on the Echo 21 Zinger 16-6 . (Glo-Bee and to much prop wash on atmosphere side of inverted carb) Is it a point of diminishing returns to go for more rpm with smaller pitch? Its rated WOT is much higher. 9500-11000

A light weight muffler source. Check out Mouser Electronics part # 546-1455C801 $ 9.84 Somewhere on their site is neat structral drawing which impressed me.
A bit of drilling and some steel brake line for compression posts.