It depends on your risk tolerance, really. 

In addition to what Wayne said the seller will have to pay imputed interest gain and will make almost or maybe ZERO cash flow if he takes this to an accountant .. or anyone who knows anything about these seller carry backs your going to have push back I suspect unless your paying WAY over market.I have sold a lot of my OREO over the years with ZERO % owner carry but always set them up short term.. 30 months 40 months that sort of thing ..

Idea behind replacing the oil furnace is avoid having the copper lines risking freezing during very cold winters, not having to worry about oil delivery and possible spills and overall it simplifies maintenance of the unit and make it more appealing with central cooling and heating.

Had I known there was a tank I would have a) not purchased the property (I passed on several properties because I didn't want to deal with an oil tank) b) had the owners remove it at their expense or c) would have asked for a significantly discounted purchase price to account for the risk.

Screening and selection of tenants is part of the risks we take when investing in real estate.

Some reject coverage immediately and some charge for the risk. 

It's lower risk and you will learn a lot more.

I am going to add into the inspection objection a point about the water heaters being original and likely to fail soon, along with full AC/furnace service in an effort to reduce the risk on those fronts. 

For duplexes is appx $500 a month in cash flow enough to take the risk on the downpayment?

Hi! I have a question for all you seasoned buy and hold investors.... or anyone with any advice really. What kind of research do you do to avoid buying property in an area that might be difficult to rent? Thanks in ad...