Need help analyzing owner finance deal

[Curtis Nesbitt]

I have 34 unit building owner is asking 4 million. The owner will consider owner financing he owns the building free and clear. He has had the building for about 6 years. The building brings in a total of 375k and the total expense is 125k. After paying all expense the building nets 250k.  After running my number I think the building will do about 187k which includes factoring management fees, maintenance, vacancies etc.  The owner is asking 3.6 million.

My offer owner finance offer:

Purchase price is 3 million 

10% down 
4% interest amortization over 20 years with a 5 year balloon