With 100-year-old properties, it's quite likely we're talking about converted hot water gravity systems and in a place like Jersey City, converted coal burning systems.

@Robert Burns I do the same as @Jim Pellerin.

You'll make mistakes and have surprises, but hopefully you'll not get burned.

Too much squeeze for too little juice, and you'd be very close to getting burned on the deal should you have an unforeseen major expense such as a nightmare tenant you'd have to evict and/or capex such as replacing the AC or roof. 

You may burn some bridges by shopping around, but I like to be very clear with agents that I am talking to others so that they aren't surprised.

He had done a few investments in the past, but sounded like he had been burned a couple of times.

Don't let your money burn waiting on the sidelines. 

If you have cash you want to burn and can accept that you may end up loosing money on the flip.

The people who got burned were forced to sell during the last recession. 

Too many sellers get burned by people coming back and wanting to crack the contract open and want a concession over something they saw in the basement (while supposedly "just checking the measurements on the upstairs bedroom").So you can go in no inspection then try and call to schedule one, only to find out that if you step foot on the property you are trespassing.Just my 2 cents