Patrol89
One thing you will find with the Honda's is that they like clean fuel. I look after quite a lot of 20hps and I advise people to fit a small viewable water trap/filter. The honda's are very fuel efficient therefore use very small orifices to meter the fuel in the carbies, it only takes a small amount of water/moisture or dirt to block these holes and then it will give you problems.
Heres a good tip for you, ask the dealer to show you where the mixture screw is and the carby drain. When you get it home and its running nice mark the position of the mixture screw with a permanent mark of some sort, then carefully screw the screw all the way in counting the turns until it seats lightly then undo the screw to the original position set by the dealer.
next time you have this problem, Drain the carby incase there is some moisture in it then get the engine going and keep it running using the throttle then undo the mixture screw 2 -3 turns and rev the engine hard, this could suck any small amount of moisture thru the carby and clear the blockage.
I have done this a few times and some times you can be lucky
A small water trap will save most of these types of problems
cheers
Garry