Make sure you have a secure mounting system for the engine and it is properly loaded with the correct propellor. Once started, you should be able to adjust the high speed needle valve slowly to get as high an rpm as possible then back it off about 1/4 turn. The low speed needle valve will most probably have to be tweaked a bit one way or another to get a good idle when the throttle is retarded. This low speed needle valve is usually very sensitive and very minute changes can make a big difference in how well it holds an idle and how well it responds to quickly going to wide open throttle. If it dies quickly when you go to WOT (wide open throttle) richen the low speed valve a bit; if it slobbers and does not respond well to WOT then lean the low speed valve a bit. There is a slight interaction between the high speed valve and low speed valve so if you adjust one, you may have to make small adjustments to the other. As the engine gets broken in, you should be able to get an increase in rpm from what you had initially.