Today was the day I broke in my ST 90, China made. I was a little skeptical at first but what a jewel.
Broke it in on one gallon of Omega 0% nitro, 17% 70/30 syn/caster oil blend fuel. Added 114 ml of castor to bring it to 20% and a 13x6 prop.
14oz Tank.
Run rich, 3 turns out, on first tank.
2nd and 3rd tank, 2 1/2 to 2 1/4 turns out.
4th and 5th tank, 2 1/4 to 2 turns out.
6th and 7th tank, 2 turns with the pinch test.
8th tank, 2 turn and finding optimal setting with tach.
9th tank, set the idle.
Now I must say this engine got stronger and stronger. Has great transition from idle to full power and the mid is fine.
You could definitely tell it was breaking in great with the different rpms it would run through.
Keep in mind this is with the throttle set at full open.
It never leaned out totally and ran flawlessly.