I would also ask, where exactly do you have the C clip on the needle valve of the carburetor ???
If your running a stock NT or BoFeng carby that comes with the 2 stroke motor kits, it should be in the middle notch/groove of the needle valve at your altitude of 617 ft above sea level.
If that still proves to be too rich, then go upwards on the needle valve to the next to the top notch/groove to lean it out a little more if necessary...There should be 5 notches/grooves on your needle valve...DAMIEN