50% rule on current rental property

[Chad Phillips]

4 years ago I relocated my family for career purposes. We made the decision to rent the house we own in South Caroline.  instead of selling. We current rent in Georgia and would like to officially begin investing in real estate. We now would like to purchase a home with the intent of doing a live in flip to begin our real estate investing future. Would selling the rental or keeping it makes the most sense considering the following?

mortgage on our South Carolina rental is $1250 per month. Our tenant pays $1600 per month. The house is worth roughly $215000 with a rough estimate of $7500 in upgrades needed. Currently, we owe $143000. 

Considering the numbers and the 50% rule, the house is cash flowing. Should we try to keep the house as a rental or sell it? Thanks for all responses!