Although I personally preach out of the King James, it certainly is not the most accurate available at this time. The ASV of 1901 is just one of those which are closer to what we know of the original autographs. Another very accurate version is the RSV.
So you ask, having said that why do you preach out of the KJV. Notice I did not say anything against it, I simply point out that from a scholarship point of view it is not the most accurate. Secondly, I have never seen or heard of anyone being offended or upset by a preacher using the KJV in the pulpit, while the same cannot be said of any other version/translation. EVery other that I know of has someone who trys to disparage it, usually those who have never studied the issue.