Look for a rectangular aluminum plate on the left side of the clutch housing near the front of the machine (the right side if you are facing the machine). This is the serial number plate.
Find the serial number located in the box labeled "Serial No." The serial number for the H and HV models will begin with the letters "FBH." For the Super H and Super HV models, the serial number will begin with the letters "SH." There are several styles of serial number plates. The serial number will most often appear in a white horizontal box in the middle or the upper-right corner of the plate.
If you are unable to read the serial number due to fading or smudging, hold a thin piece of paper firmly on top of the serial number plate and shade the entire area with a pencil or piece of charcoal. This technique may reveal the serial number on the sheet of paper.