(vacancy, emergency repairs, tenant takes months to evict, rents could drop in your area slightly)  If any of that stuff happens and you have been taking the small amount of cash flow you are more likely going in the hole on your investment at least for that period of time.    2) If you plan to buy more properties and take financing on them the lender is going to qualify you based on how much you HAVE to pay in payments every month.  

I find that tenants don't want to be bothered and only call for emergency items e.g.

DO NOT put all 15K in a "turn key investment" And take what you hear on here with a grain of salt.You need to keep reserves.if $15k is what you have, you should prob keep the majority of it in a savings account as an emergency fund. 

Your property manager should be responsible for responding to emergencies at a moments notice (like water or gas leaks), and fixing issues (like plugged toilets, broken appliances, water heaters, or HVAC, etc.), holding your tenants accountable for regular maintenance (changing HVAC filters, lawn & yard maintenance, checking their smoke detectors regularly, etc.)  

Last night, I was thinking about section 8; unfortunately, the city stopped issuing vouchers but I can inquire about emergency housing aid. ...The price is discounted to reflect the loss rent.

I could pay it off (I owe $185,000) and have about $10,000 in emergency savings leftover.

I planned to use $20,000 for down payment and keep 15k for closing costs and an emergency cushion.I was seeking $60,000 for 6 months and willing to pay 10% on that loan and secure it with the property.

To me, when a person rents a home from me, that home is THEIRS until the last day of their 30-day notice.  24-hour notice for repairs or immediate access for emergencies aside.With that said, I will ask my tenant if I can do some showings with a 24-hour notice. 

Your cash reserves, in an emergency, will be king if you have it on hand but will be reserved cash you will have to try and get to fast if it's tied up.

The savings can go into an emergency fund for vacancies, repairs, etc.