I think you will have the black painted ali engine on this with a Zenith carb. If so you should proceed as follows.
Ensure you have enough fresh clean fuel in the tank & the tap is on.
The throttle usually has an engine kill built in when shut right down. Open throttle to about a 1/4.
Just above the air filter will be a lever for the choke. Rotate lever to the horizontal. This will apply the choke.
Pull starter rope and hopefully in a couple of pulls (all being there is no fault with the mower) you should get engine started.
Once firing gradualy ease the choke back to vertical.
You should now be in action.
To stop engine shut throttle all way down to stop position.
If restarting from warm/hot you should not need to use the choke again.
Hope this helps & good luck.
Robin S, August 2008