On all of my flights on FS I always get 'overspeed' just as I have tkaen off or when I start to get to cruising height.
Any way to stop this, and how do I reduce the throttle on Boeing jets as I am only using F1 and F4 at the moment is there a medium?
You need to keep your speed under 300 KIAS at around 30000 feet. It changes from aircraft to aircraft. Each aircraft has their own max speed. I suggest you go through the learning center and find these max speeds. F2 and F3 reduce and increase throttle slowly.
or you could just pull up the throttle in the panel and do it that way
All the Boeing jet have autothrottle, don't they? Use it-- that's way easier to control than the trottle levers. Keep it below 300 kias up to about FL260, then switch over to Mach numbers and set it to your plane's maximum. Piece o' cake.