Rental property, sale or hold?

[David Ronquille]

Hello all, Can someone please advise me?

I started buying rental property for years ago. my first purchase was an owner finance of two properties one being a duplex and the other being a single-family for 15 years. I paid 120,000 for the single-family that needs some renovations. Currently the rent only covers the mortgage, insurance, and property taxes. Since then I have bought two more duplexes and one four-plex. my question is my tenant in the single-family wants to purchase the house. I am debating if I should sell it or not? If I did sell it, I would sell it for 150,000 take the cash and pay off the four Plex, which would bring my mortgage down to 11 years instead of 28 years. Although I have no cash flow on the single-family, I do gain $6000 a year in Equity in the single-family. My mortgage on the four Plex would only change by $60 a month. Any advice would be helpful thank you