What to do with rental

[Todd Cianciulli]

I currently own a rental home. It was once my primary residence and now a rental. It is on a 30yr @6.75% term. It is currently one year I to a 3 year term renting at the top of rental market. I have an opportunity to refi at around 4%. If i do balance 135000 refi with market value at about 155000 at 4% I could generate a 300 per month cash flow out if it. Currently it is a negative cash flow. Should I refi and keep it as a good rental or sell at my next opportunity?