Would you have the model number off the engine> It will be example FG560-OOCG. A letter number combination. Do you have an electric solenoid in the carburetor? It would be a fuel shutoff that has to stay open for engine to run. It should click when key is turned on. It plugs the main jet of the carburetor and if it closes, engine stops and will not restart. Solenoid can go bad, or it can loose power to it. Here is example of solenoid.
Difficult to read but looks like G08A71 type3616
Other no(NNN) NNN-NNNN No solenoid on carb. Switch on r/h side of engine, not key start.
I will adjust plug, carb had very little dirt in it and the needle was clean, bowl was also pretty clean.
Will do this and come back to you.
Set plug gap as suggested, no changed so stripped carb cleaned thouraly all jets needle and bowl, not really dirty.Engine eventually after several pulls, normally 2 pulls. Ran poorly and stopped again and again. So no difference than before. Why. What do l do now to cure problem?
You were quite right about the carb, tiny piece of dirt hardly visible to the naked eye, everything now hunky dory. Thanks Curtis for your help and patience.