Sewage Smell in old basement. I think I found the culprit?

[sholt1190]

The lady and I bought an old house (1910) in Newport, RI about six months ago. We love the house, but as the summer months crept in, we have been tortured by a disastrous sewage smell. I am not exaggerating! It started to creep up all the vents and rooms throughout the house, and the basement is pungent. After having multiple plumbers come and take look, the conclusion was there has to be a dead animal causing the smell—mainly because there were no leaks and the plumbing seemed legit. As the smell continued, and even got worse, I brought a couple of my contracting buddies down into the basement, we started digging around, and low and behold HIDDEN (probably by the previous owner), was a hole in the basement, completely open, that was most likely the old opening to a sink drain. I am attaching pictures for reference. The pipe to the right is the sewage pipe. Hole is to the left in between the wood planks. I'm guessing when the installed sewers they connected them?

Any thoughts? Am I correct on this? There was an old PVC cover right next to it, that must have been placed on top of it prior to this. I am hoping that stops the smell. For whatever reason, someone took it off at some point in top and never put it on top again.

Thanks in advanced,

Shaun

 

[Reach4]

You can measure the hole, and get an expandable plug.