Speaking as a technical guy, my default position is to be turned off by co-founding with a business guy unless they have an amazing track record. I like the advice of earning a technical co-founder.
I just wish more business guys realized their ideas aren't that special, aren't a magic way of printing money and just coming up with the idea doesn't entitle you to 75% of a two-man venture. It doesn't even really entitle you to an extra 10%.
In the beginning, your job is probably going to be to find a place to work, deal with the guy who's installing the Internet line, buying computers, buying food, buying and assembling furniture and generally just making things work. That's all very unglamorous work but, depending on the venture, it's quite likely your (alleged) business skills will be of very little value (while you're building a PoC/PoS/MVP).
I don't think I'm alone (as a technical guy) in generally finding business guys to have an inflated sense of self-importance who often want to treat technical people as an exchangeable/replaceable commodity.