Vertical internal combustion engine

A vertical internal combustion engine having a cylinder block containing a crankshaft directed substantially in a vertical direction and a plurality of cylinders arranged along a vertical plane including the crankshaft, comprising:

• a pair of balancer shafts drivingly connected to said crankshaft, and being pivotally supported in said cylinder block and disposed in parallel with said crankshaft on opposite sides of said cylinders;
• pivot holes for pivotally supporting each balancer shaft being formed at uppermost and intermediate crankshaft supporting portions of said cylinder block passing through crankshaft supporting portions on said cylinder block;
• a lubricating oil supply means being provided at said pivot hole of said uppermost crankshaft supporting portion;
• a work hole for working said pivot holes formed in a lowermost crankshaft supporting portion of said cylinder block positioned in axial alignment with a center line of said pivot holes;
• and
• a removable plug closing said work hole tightly,
• wherein said lowermost crankshaft supporting portion is divided into an upper wall and a lower wall between which an oil passage space is interposed, said lower wall extends radially slating downward and only the work hole of said lower wall is closed by said plug.