I can't emphasize enough that it isdn't enough to be a great mechanic ... you have to be a businessman too. I spent many years helping small businesses (I'm a business prof in my "spare" time), and I honestly cannot tell you how many genuine craft masters were struggling or failing because they lacked basic business skills. I was working with a restaurant owner once, and he finally complained "Everyone has to eat, don't they?" My answer was..."Yeah, but they don't have to eat at your place!!"
Check out the Small Business Administration and your local community colleges first. Look at http://www.sba.gov/
They used to have a program where retired business people would give free advice to new startuips...maybe that is still in effect but I don't know, the SBA has been drastically reduced (makes sense...right??)