The Mongols not only ravage Europe but capture Japan and, following Japanese fishing routes, discover America in 1290. The Mongols conquer Toltec Mexico and the Incas while some Europen refugees settle in Vinland. The Black Death is much worse in Eurasia than OTL (80% toll), but leaves the Americas mostly alone. In 1902 the technology is roughly equivalent to OTL 1730. Mongol-Chinese-Siouan-European hybrid states rule from the Great Plains, and cities along the Mississippi are developing steamboats.
Plausibility (aside from unlikely Black Death mortality)?