I recall when I ran mine first time, I had to open up the low needle to about 2.5 turns out to get it started.

Some other hint.

. definnitely use nylon pushrod for the throttle servo
. PCM receiver is preferred
. make sure the mounting is solid as a 50cc engien is very powerful. For example, use 1/4" aircraft plywood for the firewall.
. balance the prop and tighten the prop bolts
. proper separation of receiver system from the ignition system (12" recommended by book). Do watch for interference induced by the ingition
. ask a field guy to check the setup before fly