A 66-year-old Vancouver man is dead following a motor vehicle accident late Sunday morning on Highway 14 in western Skamania County.  According to the Washington State Patrol, the motorhome driven by Kenneth Karschney was eastbound on Highway 14 about seven miles east of Washougal when he lost control and left the roadway to the right.  The motorhome when down a small embankment, struck a tree, and then caught fire, fully engulfing the vehicle.  Emergency personnel arrived on the scene shortly after the accident and contained the fire, but Karschney was pronounced dead at the scene.  The accident remains under investigation.