I have a Honeywell Beckett oil burner/furnace that is less than 8 years old. We've lived in our home for 6 years now, and it has been running like a champ the whole time (no problems whatsoever). Most years I turn the furnace off in May once the weather warms up seeing that we have electric for our hot water and don't need to burn fuel oil during the warmer months. This past fall (September 2015) I had it maintenanced/cleaned just to tune it up and make sure it was still in good working order.
This past spring (Mar 2016) we had a flood in our basement and the water got several inches deep. Within hours I was able to pump it out and the furnance continued to run like a champ (again, no problems at all).
The last several weeks have been very hot (mid-90s) during the day, but fairly cold (low-40s) at night, and so I have not yet turned the furnace off like most years.
I just went down into my basement and see/smell this:
What is going on here?!? What do?!
CRITICAL UPDATE
So things just elevated by several orders of magnitude (in between my posting this question last night and this morning).
This morning I just happened to get up early. I was downstairs on the computer and heard the furnace kick on. I figured I would go down into the basement and see if I could see anything visibly leaking.
Instead, what I saw was far more horrific. Billows or dark grey smoke were pouring out of the vents and piping of my furance. I quickly flipped the kill switch for my furnace, turning it off, but the smoke kept pouring out.
I readied pitchers of water in the event flames broke out, and began the procedure of evacuating my family from our home.
Luckily, after about 10 minutes the smoke cleared out, and I am continuously monitoring it every 10 mins or so. I think we're out of the "woods", as far as house fires go. Had I not woken up to do make some open source contributions, I likely would have woken up with the entire house on fire, or perhaps not woken up at all. Thank you GitHub.
From what little I've been able to research so far, I think what happened here was a "puffback" (I don't have enough rep to post more than 2 links – just Google "oil burner puffbacks"). I think I have an oil leak somewhere, which explains the oil sitting around the base of my furnace (in the photos above). And when the furnace kicked in just 30 mins ago, some of that pooled fuel started to ignite. So I guess, now, I'm looking for someone to help me confirm my suspicions.
Best Answer
From reading all that you wrote, including the update, it is clear that there is an oil leak somewhere in the furnace mechanism or in the fuel line leading up to the furnace.
You should continue to keep the furnace off until you can get an oil furnace repair professional in to take a detailed look at what has gone wrong and get it fixed properly.
You will most likely want to take action to clean up some of the spilled oil too. One thing to help with that is to spread a layer of the clay type of cat litter material over the spill area and work it down into the concrete.