Bumps yes the correct position of the poppet value is in the C position.
If your having revving issues (and is sounds like there's been lots of work on the carby)check your decompression valve.Pull it out it should be in the open position.You can suck on the pipe which should close the valve.I have had problems with them in the passed and it gave me the same problem you have.Although it did also allow the engine to over rev as well.Certainly no harm in checking.After-all it's only a 3/4 spanner only takes five minutes.
