Take the wheels apart. They most likely have a one direction gear
drive. Basically this setup allows the wheels to be powered going
forward but freely spin when not being powered.

The parts get gummed up with dirt or dry grease or sometimes they
wear out. Hopefully you can just inspect, clean, re-grease and
re-install.


Thanks for the reply,but the set up underneath is the vee belt goes
from the blade pully to a pully on a gearbox which is mounted to the
rear axle .When i operate the drive lever on the handle there is
intermitent drive,or if i lift the back wheels up there is drive .Dont
know if it is a fault with the gearbox or something else

What is intermittent? The axle rotation or the wheel rotation?

There may be a small mechanical type clutch/drive assembly located
between each axle end and each wheel. Contained within the wheel.