2001-2002 Yamaha 50HP F50Z/T50Z Ouboard 4-stroke engines service manual, Page 184Get this manual
IpOWRIIfriJ: IPower unit 4When installing the main bearing, insert the projection of the main bearing into the slot on the cylinder body#4
Remove any small metal particles and oil from the contact surfaces of the cylinder body and the main bearingMeasure the main journal oil clearance with piece of Plastigauge (PG-1)
Crankshaft main journal oil clearance: 0.012-0.036 mm (0.0005-0.0014 in)
If the oil clearance is below specification, check the main bearing color and clean the contact surface of the cylinder body and the main bearing, and then check the main journal oil clearance againS62Y5A20
If the oil clearance is over specification, install an oversized main bearing, and then check the main journal oil clearance again
Connecting rod cap markcolor IIRed IIRed II1Blue II1Blue IIIIYe II ow IIIIYe II ow