Backing up a page, the Wright blade saws do not have a shaft extending from the crankcase to drive any accessory outputs. The earliest models actually had a rod connected to the top of the piston to drive the blade, with seals on the top of the cylinder head. Later models had a second throw on the crankshaft with an independent rod to drive the blade. The blade moves whenever the engine is running, if you push the trigger to one side when you release it the engine continues to run, if you simply release the throttle trigger the engine will stop.
Mark
Mark