Hi I have a O.S. Cv-Rx .12 and it keeps cutting off like not even 2/4 of throttle im not sure whats wrong i just got it and it didn't do it on the first tank but on the 2nd tank it started doing it please help i tried richining it more and tried to even lean it out a little.

If an engine won't run well much past low throttle, it's likely that the idle mixture's not set correctly. During the breakin running, we usually leave the glow ignitor on the engine and drive it around. We accelerate up and down the parking lot, getting up to full and back down. We gradually work the high-speed needle towards peak RPM. After a few tanks' worth of running, we then work on the idle mixture. After a few tanks, the engine's run-in well enough to accept being set to a good idle.