goinfasterthanu
if you have and adjustable FPR and FP Gauge (which you should have already anyways) make a note of what your settings are at BEFORE the pump, then if anything changed, just turn the FPR till you get to the same FP.

i have never personally seen a walbro 255 make a car puff black smoke out, but if your FPR cant regulate the PSI in the rail , ie, its leaky, then you might have richness.

but dont worry about it, im just telling you sypmtoms to look for, any issues let us know