Mine will run for 10 to 15 mins then shuts down

Sounds to me like you have some water in the carby. To check this, loosen the little screw at the bottom of the carby bowl and catch what comes out in a cupped hand. ( you may need to put it on bricks to do this).
If you do have a globule of water running around in the petrol you catch, draining it here for a few seconds with the fuel tap on may be enough to fix it. I would always check the water trap on the bottom of the fuel tap at the same time though.
If this only works for a little while, you may need to remove the fuel tank and drain & dry it with a rag and stick.
Having said all that, I have had similar symptoms
to what you describe, caused by a spark plug, so that is another quick and easy thing to try.
Hope this is of some help.