Subaru Dune Buggy Designs I Have A 6.5 H. P. , 169cc,ohc/ohv, Robin/Subaru Engine, Mounted On A Scorpion Dune Buggy.When Moving It?

I have a 6.5 h. p. , 169cc,ohc/ohv, Robin/Subaru engine, mounted on a Scorpion dune buggy.When moving it? - subaru dune buggy designs

reported a cloud of white / blue exhaust mile.The each half throttle. I have the spark plug. Are there any opinions on how to solve the problem?