Hi Max and AVB,

I decided to have one more go before I sent it for recycling. On your advice Max I changed the spark plug to one from a good running Chonda I have here.
After a few pulls with the fuel tank topped up away she went. I had pulled the carby apart to check the main jet previously so I just needed to get all the springs in the right place and adjusted the choke and I mowed my yard with it.

Alls well that ends well I suppose. I wouldn't have tried the plug if you had not suggested it Max. I think it's only fouled from trying to start without spark. I'll clean it and see how it goes in the other machine.

Thanks again for your help. My grandson will be delighted. He will get it back with a little advice.

Jeff