Hi Miguel
I had one of the original Suffolk punch mowers dating from the sixties or seventies. I'm not sure whether the present models are similar, but in general problems with mowers are either due to lack of a spark or fuel blockages.
Check the vent in the fuel cap isn't blocked. The original Suffolk punch mower had a primer button on the float bowl (a reservoir working like a toilet cistern which fills until a float rises and blocks entry of fuel). Push down on this plunger and the bowl should overflow if it is filling ok.
Sometimes the valve allowing entry of fuel into the bowl becomes blocked by debris. Turn off the fuel tap and remove the bowl (It will be held on by a bolt, or couple of screws) while holding a jar underneath to collect any fuel. Turn on the tap and check fuel flows freely. Remove any debris from the bowl and replace.
You can check out my troubleshooting article about lawnmower problems on HubPages at http://eugbug.hubpages.com/hub/Why-Wont-That-Lawnmower-Start
Euge
November 2012