I'd sell because you are reaching the time when you lose the cap gains exemption and that $24K would take over 2 years of renting to get back.I had a condo that I owned for a long time and I sold it despite it being paid off and having long term tenants. 

Every time you lower your tax bracket you are lowering the value of the deductions.

Investment Info:

Small multi-family (2-4 units) buy & hold investment.

Purchase price: $98,500

Cash invested: $15,000

owner financed on duplex, bought from a friend of the family. hopefully many ...

Also, our market has many First time home buyers, so to fix&flip we needed contractors which required much more $$.

And even then, the life cycle is generally pretty long from first contact to closing.  

I'd be happy to talk w/you on the phone and maybe meet some time for coffee. 

And, factor in the depreciation and other tax benefits, deductions, home office, vehicle expenses, etc. 

I bought my first house 2 years ago for 255k 20% down at 6.375% APR.

Quote from @Michael Long: Long time reader, first time poster!  

In the first you have one tenant, 2500/mo revenue and higher costs.