Okay I resoaked the carb components, made two gaskets for either side of the insulator, used fresh fuel and same problem.
The engine runs nicely in the 4th choke position but I really think its the flywheel effect of the mulching mechanism which keep it spinning over nicely.
Starts first pull and idles in 3rd spot nicely. When you accelerate in the 3rd position it does belch a little black smoke and runs the revs up nicely. once in the middle of the rev range I slip it to the 4th position and it seems to run fine. 5th position makes hunt.
