90% of the time this issue stems from a slight lack of oil within the chipper or mulcher. Simply add 50ml of oil to the engine and this should solve the issue.
If this does not solve the issue, a rare case of the engine sputtering and cutting out may be due to the way in which the petrol was filled into the tank. When filling up the chipper with petrol, ensure that the funnel is completely dry and that no water is entering the tank.
If this happens, the water sinks directly to the bottom of the tank and the engine then attempts to burn this first, resulting in the engine spluttering and cutting out.
To solve this, empty some of the petrol using the plug at the bottom of the machine.