I also figure repairs to bigger assets would be much more complicated such as the mechanicals.

He found more rotten beams, mechanical issues with the heating, the pipes to the water heater was hazardous and can cause leaks.

I'm curious about some of the mechanics? 

My plan is to keep my current job as an Industrial mechanic, and invest on the side while still working my full time job.

It causes me a few extra trips a year to reset a breaker, but I have to believe it makes the tenants more prudent about overloading if they know they have to call me to get it reset.Other than resetting the breaker, I can see no other good reason a landlord would allow tenants access to the basement mechanicals. 

Also what would guarantee the partner would get their money out, mechanics lien?

I'm a 50 year old Industrial Mechanic, so I can fix just about anything, and my wife is a Industrial Electrician who has went on to get her engineering degree.

With only 1 or 1.5 bathrooms, there is also less mechanical things to go wrong which gives you a lower cost of operation vs. houses with more bathrooms.

Besides face lifting the units what is the condition of the mechanicals?

If so, is there a mechanism for them to attempt to claw back taxes?