Hey Craig,
On the surface it looks like a good deal, but the X factor is the repairs - though you have a buffer due to it already being fully leased. Also, to second what Christopher said, get a copy of the leases. Also, I would ask for rent rolls to try get an idea of the tenant's payment history. Buying a property with tenants in place is a double edged sword. When it works out, it's awesome - you're up and running as soon as you close. When you inherit problem tenants, not so awesome. I bought my first two properties with tenants in place. Three sets of tenants in all, since my first was a duplex. My record of this working out is 1 for 3. The first tenant was great and she is still renting from me. The second were in the process of buying their own home when I got the property, so I lost them. The third were having a lot of problems, and I reluctantly had to evict them eventually.
Regarding monthly expenses - I'd estimate that 65-70% of your gross rent will go to expenses (including taxes and insurance, but not principal and interest). The 50% rule doesn't work for properties like this, because you are paying utilities, and because it is a quad (four of everything, and typical tenants are a bit rougher). That sounds like a lot, so here's how I got there:
Gross rent (yearly): 21,600
Vacancy: 2,160 (turnover is faster for quads, so you probably want to estimate 10%)
Insurance: 706
Taxes: 1635
Utilities: 3384
Repairs/Maintenance: 1620 (7.5%)
I usually guestimate 5%, which is ok for SFHs, or a duplex in good condition. But for a quad I think it's prudent to go higher.
CAPEX: 1620 (7.5%)
Reserves you save for things you have to buy rather than fixes - new roof eventually, AC, hot water heater, range, fridge (if you provide) etc. Again, this is pricier for a quad due to four of everything.
Management: 2160 (10%)
Leasing: 1237
Management companies typically charge 1/2 month rent for leasing, on top of the usual 10% for ongoing management. For a quad, definitely figure two vacancies per year, or three to be more conservative. Around here (I'm in DFW, so it may vary for you in OH), the typical length of tenancy for a SFH is about 2-2.5 years. Duplexes are more like 2. So I would figure 2 years as a best case scenario for a quad. If you say 18 months average, that equates to 2.75 vacancies per year.
Total Expenses: 14162 (65.6%)
Net Operating Income: 7438
Debt service (P&I): 3066 (I assumed 30 years at 5.5%, with 25% down)
Cash flow: 4371 (364/month).
Figuring 15000 for your down payment, and closing costs of around 4000, that's about a 23% return on your 19000 invested. But that's without accounting for initial repairs, which is the big unknown.
If you're lucky, you inherit some long term tenants that are really "dug in" (technical term for having been there 7-10 years and never planning to move). You may not quite get market rent, but a lot of that vacancy cost goes away. It's definitely possible to do better than the numbers above - you just don't want to count on it.
To condense everything above into my gut reaction - risky, definitely potential for headaches, but potentially profitable.
Hope this helps. Good luck!
-Harry