Thanks for your response:
1. Regular unleaded fuel with 2- stroke oil as have always used.
2. Fuel is fresh.
3. Mix ratio of 25:1 as have always used.
4. Happens without blades touching grass. Tried it today on the pavement.
5. Vacuum hoses and carby housing seem ok but that is one thing I can check again in detail to be sure.
6. Never had a service as such. Always taken it apart myself and cleaned it. No washers added to it.
The last time I mowed the grass it was going great for about 15 minutes then suddenly started to splutter and dialed back the throttle to keep mowing at lower revs. After a few minutes I pushed the throttle forward again and It was good for about another 5 minutes then started to splutter again.
