Lawnmower - works when it feels like it! (IP1)

1 lawnmower, I bought it second hand, it's lightweight and great for a small lawn.
 Nothing wrong with the motor, but it is very temperamental to start, you have to press a button on the side and squeeze the handle, but I can't get it to start reliably.
 If you want to take a chance on it or take it for spares you are more than welcome.