RE: Moki 210
mugendkidd is right.....15% is too much nitro for this engine. I have been running the 210 for a few years and get the best results with 5% Omega fuel, APC 20x8 and a OS 4-stroke plug. Also keep in mind that if your engine is new, it will take a few gallons of fuel to get it broken in. After break-in, I am getting about 8200 with the set up above. I am also using the Cline regulator fuel system, which I highly recommend. This system pressurises the fuel tank and forces fuel to the engine through a regulator which allows the engine to pull what it needs.