Ask HN: Offer given as a cofounder

I'm looking for a startup opportunity in London. I was given an offer to be a startup cofounder. B2B app for finance market. The team will be me an a business guy. He is giving all the money for initial stuff (hardware/desks/software/hosting) as well as my salary. The offer is 24k (50-60% my market value) and 10% with standard vesting schedule. He is not going to take salary.

Risks: - Don't know him very well - He is not technical - He's first motivation is to have a company that produce cash rather than sell - He knows the market, but I don't - Possible regulation or data issue (don't know if we can store it on Amazon)

Let's break it down. After 4 year I will have 10% change to have 3% of 20mŁ. That gives expected value of 60K in stock and 100k in salary which is 40k a year. Assuming I'm going to work 80h a week that gives me 20k a year for a risk free corporate job.

Is it a good deal? Should I ask for more? Maybe different deal when he's money will be company's liability? Should I get a layer to advise?