You should never run without Castor. If you want your engine to last long, you need to always run fuel that has some castor in it. The synthetic oil does not have enough film streingth and will allow metal to metal contact at high pressures. Im very disspointed to see people giving you bad advice. Synthetics in model fuels are just not up to the job, and many manufacturers specifically recommend castor in their engines. I would not run any of my engines without castor in the fuel. Just buy fuel with castor in it, its easy.


15,000 is way to much RPM for a 4 storke, the book will say around 11 and change max. Use an APC prop, wood props are to thick, and do not have good airfoil sections due to limitations building with wood, and very inefficient compared to the APC. Much of your power is being wasted when using wood. The rest of the world stopped using wood props in the 1930's, its time for the modeling world to figure it out.