cash out refinance or holding to pay off

[Long Khang]

I bought one duplex in Boston in 2010 for 387,500 with 25% down , 4.75% for 15   years   fix  rate.

I collect 2,600 monthly,  I have negative cash flow. Two years later I cash out refinance 10k ,15y at  3% rate, now mortgage  270,000, rent for 3,300 monthly with positive cash flow. In 2014 paid 30,000 to principle with 240,000 mortgage. Should I cash out 100,000 with 30 y 4.65% fix rate and have the same cash flow? 

Long khang