According to the Yamaha guide, the outbound serial number is located on the label in the clamp bracket. The serial number is helpful when replacing your motor.
Usually the serial number is on a tag mounted on the bracket that holds the outboard engine to the boat.
I HAVE A OUTBOARD C150ztXRU
216793
235386
40tlru is the model number for a 1996 2-stroke, oil-injected, 40hp Yamaha outboard boat motor, not a serial number and not for a motorcycle.
1981
1979/1980
2005
On the hood
you can't
1985 long shaft
It is a 2003 4-stroke outboard