Thanks for the answers and suggestions of the problem. Spark always was good engine clean and always carb.problem .
Under warrenty several repairs and carb. kits were put in then the foam put in tank to stop splashing dissolved from the new type fuel and the tubes jets were replaced. the fuel pump on side of carb was replaced by the kits.
when rear of tiller was lifted to remove a rock or stick cought in rear tines fuel would pour out around filter and so over choke and end of work until evaporating fuel then start and maybe in 10 feet engine would be acting up again.
Went 60 miles to TSC. looked at there cub cadet type roto tiller and they used a Honda engine. 5 h-p and GC190 bolt sizing same so purchased and removed the Briggs and installed the Honda. Cost $265.00 and got the 3 year warrenty .
And roto tilled the whole garden with out a problem.
So never found out what was wrong but I have quit looking.
Now to get back to a retirement life.
ken