[mtmail]

I've done a 50/50 (well 49.9%/50.1%) unpaid deal once with a non-technical co-founder on a side-project. The product (website) was a key piece of course but while I started coding I gave my co-worker tasks, too. E.g. logo design, project plan, research.

Worked great for two months. He was waiting for a finished product but I still gave him tasks: write complete help pages, full FAQ, marketing plan, list of bloggers to contact after launch. I waited 6-8 weeks and got various excuses. At that point it was better to end the deal early.

What I'm saying is: make sure the co-founder is actually putting in time. He/she can't just wait for a (almost) finished product to sell. Basically make him/her work hard (with goals and deadlines and everything) for your engineering time. If he/she doesn't doesn't put in time then you might see the same low time commitment when it comes to fund raising, marketing or PR later.