Long term tenants below market rent strategies

[Cameron Collins]

Thinking about purchasing a two unit property in Lowell, Ma that's within my budget (400k-500k). Toured it recently and it's in good shape other than some uneven floors from the foundation however the two long term tenants are paying 800 and 850 per month. The market rent is around 2000-2450 for 2 bed 1 baths in the area. I am confident that a light rehab could bring the rent up to just below market(1700-1900/mo) in order to make it cash flow but I'm not sure if this scenario is worth it. Could I make the sale contingent on the property being delivered vacant? Do I steer clear of something like this? Thanks