Hard to start, only wants to idle, wont respond to throttle for ages and dies most times the throttle is used.Eventually after many attempts to rev it up it does start to behaive itself. whats up ? maybe low fuel pressure from pump or what ?

 

You probably already did this, but I always say to start with the obvious. Check/replace your spark plug, and inspect/clean your air filter. Your next step might be to clean out your carb. You would be amazed at the junk gas can have in it.

 

Already done sparkplug and airfilter. And its fuel injected so no carb to worry about although in saying that I would rather have a carb as they are easily fixable in cases like this. So still a mystery !