ORIGINAL: greggles47
!0 % nitro certainly isn't going to hurt your motor - but be sure to flush it out at the end of each days flying. If you must use the fuel you mention add at least 5 % castor.
I beg to disagree.
An engine that's designed for 0% nitro may well suffer from detonation if run with 10% nitro, especially if a pipe is used.
My MDS 61 came with an extra two head shims that were included to allow use on higher-nitro fuels. I wouldn't run it with anything more than 5% nitro on one shim and even then I detected some detonation with props at the larger end of the acceptable range.