Gray, the photo's have not come through, try using the 5th button from the left in the reply box "upload inline image(s)"
If the mower in question is a Mustang of the 70's or early 80's, it uses a locking clip, which will need adjusting, if it is a later mustang, it may need a pressure spring replaced.
If it is the mower in your avatar image, then it is a VC-160, not a mustang, and requires different work.
If it is a VC-160 MKI or MKII, then it may need the handles adjusted, but more likely needs the flap adjusted, if it s a VC-160 MKIII then it will most likely need the handles adjusted, and maybe the flap.
If you could try again to get the pictures to load, I'm sure we can be of more help.