Do you mean the GXV670? If so, look on page 13 in the manuals below and it shows you where it's located. I am not sure which manual is for your exact mower because you need to know the serial number to figure that out, but these are all for GXV670's. Make sure what the manual is describing is the engine you have, because I just looked up the GXC670 on the website, I'm not positive it's the 24HP V-Twin.