Fuel collecting/pooling in 3208 "valley"

[hsaddock]

Folks:
I finally moved the BB (first time since December) over the weekend
to work on exhaust shields and noticed fuel dripping from the engine
on to the driveway. I started to investigate the source and
determined that approximately a cup of fuel had accumulated over
time on the top of the engine between the heads, aft of the injector
pump and forward of the turbo charger. This space had filled with
fuel and the fuel was working its way out from the rear of this
valley and down the engine sides. I mopped the area clean of fuel
and saw no additional fuel appeared with the engine not running.
Later in the day, I fired up the engine to move the coach to the
back yard. Between building air pressure, moving the coach and
other activities, the engine idled for approx 15 min. After this, I
rechecked for fuel in the "valley" and a small amount had
reappeared, indicating some sort of leak when the engine is
running. I have the large box style air filter and turbo on my 3208
so visibility into this area is very difficult and I could not "see"
anything leaking fuel. Before I plunge into major disassembly, I
wanted to ask the group to see if anyone else had run into a similar
problem so I may have a list of what to check for before I begin.
If memory serves me, there was a discussion on this very topic
approx a year ago but I could not find it in the archives.
Harry Saddock
83FC35
South Windsor, CT