Partial Sellers Financing

[Kyler J Sloan]

I am new to real estate investing, and have a simple question. 

Can I do 50% sellers financing if the mortgage owed by the seller can be covered by the mortgage amount I qualify for? 

In my case, the seller of a 600 K multi-family has a remaining mortgage balance of 200 K, and I can obtain a loan for 350 K -- is there anything preventing me from financing 300 K through a bank, and asking the seller to carry the remaining 300 K? 

Thanks in advance for any feedback