Is starting a business without somebody knowing "business" a good idea?

I am a developer since quite some time. I am having some good ideas and plan to start a business in the startup world. I already have a friend who will join me as a co-founder.

Now the problem is: Both of us are developers and both of us have little to no knowledge about running a business, marketing, sales, etc.. I am not concerned about legal issues, taxes or things like this here. I am concerned about how to make our product available to the world and "selling" it.

I read about starting a product, building a MVP, validation of possible customers, some initial marketing strategies, initial networking and others here on onstartups.com and other sources. This sounds all reasonable and also doable to me, even we are "just" developers. I am wondering about the part after the initial word is out. How to do the right thing, how to sell it to reasonable amounts of customers, how to do marketing and make the product more popular.
My friend and I we know our thing around building products, most likely even great products, but even we learn a lot of business related stuff we will not be able to run all aspects of it.

Now my questions are:

1. Are my assumptions right? Is the above mentioned really the case and it is quite hard to to a business without a "business person"?
2. If 1. applies, would it make sense to find an additional co-founder which is professional in this area?
3. If 1. does not apply, is it possible to run a business without these expertise for a while and even make it successful? If the company is growing big enough it makes of course sense to hire additional people to "do the job".

Again, this is not about kicking it off, but more about getting the business rolling after its initial kick-off phase (and getting the first real revenue). I am not considering investments here as well.

Thanks for the answers and advice.

Basically, you either need to learn the skills yourself or bring someone in who already has them. This not only applies for marketing but also for finance, capital raising (if necessary), customer service and all the other components that go into making a business work.

If you think you can get the product to market, do that and then plan to hire the skills you need once you have proved the idea and are getting some traction. You will either do it successfully or realise that you need to bring in someone with other skills.

The big caution here is that you don't know what you don't know. There may be business knowledge you don't have that could make a big difference to the success of your idea. So try to find a mentor with complimentary skills and knowledge to get you through the validation of the idea so you can hopefully fill any knowledge gaps you may have.

If you don't know business, you have a lot of work ahead of you. There are a lot of million dollar ideas that never see the light of day for the simple reason that the people who have the idea have no idea how to get them to market. I agree with the above, you need a mentor and advisors. Find someone with grey hair or no hair who has been doing what you want to do for a long time. You might be surprised the advice you can get by buying someone lunch.

Knowing how to build a good product is the smallest part of doing business. You may be the most talented developer out there, but if you cannot sell it then it makes no difference. You need to read the book, "The Art of the Start". It is a good primer on the subject and helped me immensely.

You will need a third partner regardless though. Partnerships of two can easily lead to conflict. You end up with deadlocks if you are 50/50 and at anything other than 50/50, one person's vote does not count. They may as well be an employee. A three way partnership can never end in deadlock, as long as no one has more than 50% of the voting rights.. Trust me on this. I am working with a startup right now that has a $500M revenue/year idea right now, but they are a two-way partnership and are always infighting and bickering. The idea will never materialize unless something drastic changes.

No matter what, learn to sell. It is the most important skill of being in business, followed closely by managing cashflow. And yes, I put selling first. If necessary, you can out-earn your own stupidity. :) Not a very wise way to do it long-term, but pre-2008 lots of people were doing it.

You should get the book called "The E-Myth" it talks about technical experts and the very issue that was brought up above about many ideas not seeing the light of day because these experts, be they programmers, or engineer's, etc. don't partner with the business savvy people to get all that "other" stuff done.