I know they make it run and move faster....but mine cruises pretty fast in 1st gear, I can't ever imagine having to use 4th gear. Should it be in 4th gear for higher and more snow so it will shoot it farther....or does the gear not matter for that?
My blower has 4 gear speeds. I use the first two for blowing and the upper two for traveling while not blowing. You pick a slower or faster blowing gear based on how thick the snow is (slow gear for heavy snow), and a slower or faster traveling gear based on how tired you are vs how much of a hurry you're in to get inside and use the bathroom.
Throttle is mainly either idle (when not doing anything) or full on (when blowing).
The throttle controls the speed of the engine and the auger(s), and the gears control the speed of the wheels. You should normally run it at full throttle to pick up and throw the snow. Choose the gear based on the situation - for light snow in a large area use a higher gear to get it done quickly. With heavier snow you may need to use lower gears to keep it from bogging down. As Ecnerwal pointed out, the higher gears are also very useful when you're moving the blower but not clearing snow - like heading back to the garage when you're done, or heading over to the neighbor's yard to clear their driveway. If you’re happy with just using first gear, that’s fine.