A PROTECTIVE COVER WAS OMITTED FROM THE SPEED CONTROL UNIT. WITHOUT THIS COVER, A BEAD CHAIN WHICH CONNECTS THE THROTTLE LINKAGE TO THE SERVO ASSEMBLY COULD BECOME ENTANGLED IN THE LINKAGE OR OTHER ENGINE COMPONENTS. IF THE CHAIN BECOMES CAUGHT, IT COULD CAUSE THE ENGINE THROTTLE TO LOCK OPEN. A THROTTLE ARM WAS ALSO ACCIDENTLY OMITTED FROM THE SPEED CONTROL UNIT.