Mantis starts ok, and idles just fine, but when you give it gas it dies?

Dirt in the high speed jet put a clamp on the fuel hose in front of the fuel bowl remove the screw in the bottom of the bowl this is where the high speed jet is 2 little holes need to be cleaned out with jet spray gum out use to tube that comes with the gumout clean it well clean up into the bowl too
reasemble and should work fine be carefull not to loose fuel bowl jet or damage the needle dont put know pressure on the float

Start with the basics. Check condition of fuel lines and fuel filter. May need a simple adjustment by backing out on the low mixture screw just enough to give you a smooth "throttle up". You may also need to open the high mixture screw to obtain proper high speed. If adjustments do not correct the problem, you could be looking at overhauling or replacing the carburetor, whichever is more cost effective. Hope this helps.