As soon as I start the engine it runs wide open and faster than it ever has

I suspect a cracked or damaged exhaust component - that could be an exhaust manifold or point of coupling of the pipe to the manifold. As the exhaust heats - the components expand and effectively seal or reduce the area of the opening. You ought to have this checked and repaired as letting it go (if that is the problem) can cause the catalytic converter to fail and cause fuel economy can suffer, too.

if your saying your saw runs full speed as soon as it starts , one of two things is happening :
(1) your low speed carb jet is too far open
(2) your throttle trigger has disconnected or become stuck from your carburetor and now the throttle blade inside carb is full open

If the plug is wet, it is likely fouled and the cylinder flooded. Dry off the plug and reinstall it. Open the choke and throttle so the carb throat is wide open and crank the engine over. This will evacuate excess fuel out of the cylinder faster then anything. It should fire at least once.

Reconnect the governor rod back on to the carby throttle butterfly correctly. When stopped the lever will hold the throttle wide open and as it starts the lever pushes /pulls the throttle closed to the idle stop screw

You have one or more bad injectors stuck wide open, and is dumping gas.

could be air cleaner clogged and/or crankcase ventilation
breather or tube to air cleaner frame work clogged

Are you sure you engine RPM's are high enough? If so adjust you carbs.high speed screw with the throttle in the wide open position.

You may have a large Vacuum leak,

Reving in neutral does not mean the same thing as under load. If you need to pull 4500rpm under load and for an instant the load was gone, you would probably overrev to 6500. With the cover off and motor not running move the throttle to full forward. Look at your carbs and see if the throttle plates are wide open. If they are not all wide open take it back to the dealer. The throttle adjustment is off. You need the full range of travel from idle to topend.

It sounds like the needle valve in the carburetor is stuck open. The carburetor could just need a simple cleaning or you may need a new carb. kit.
If the carb. parts (needle valve, gasket(s), diaphragm, & small screen) are more than 3 to 4 years old, you should go ahead and buy the carb. kit. Otherwise just clean the carb. If you need advice on how best to clean the carb., just let me know.

Jim