Hi Nz, only on a Lawn Mower...
It was a hot summer day, loads of long grass to cut, and the engine kept stopping after over 15 minutes running. It did this several times, but would restart after a 10 minute break.
When I finally twigged what was happening, I could see bubbles from the petrol pipeline bubbling into the fuel in the tank. This pipe was sitting very close to a hot part of the engine.
Re-routed the pipeline, and held it in place with a cable-tie, and all Ok ever since.
Pete