i bought mine bout 2yrs ago, just because it was a new American HH.....and I REFUSE absolutely REFUSE to buy chinese if i can buy American. I paid like 250.00 for mine from a man out in Georgia.
The FDC is (from what I gathered) a valve that compensates for the different viscosities of different fuel and will open up or close the valve so the IP can use Kerosene, DSL, WMO, Aviation, WVO......heck probably piss if its strong enough ( Im not gonna ask, nor will I find out to let ya know-gross)....BUT you can enrich the IP by turning up a nut..some call it a Smoke screw, some call it a Droop screw....I call it a turner upper.
But, yous and I's is in dee same boat homey....I just grabbed my garden pump sprayer to get DSL in there instead of ether. Just makes sense, some how.