Small Engines (Lawn Mowers, etc.): high R.P.M., throttle plate, engine rev

Question
QUESTION: I have a Toro Powercurve 2 stroke snowblower.Machine model # is 38409 serial # is 9900270
engine-family # is WL4XS.1415AA  Model # is 98-7005
The problem I am having is the rpm is revving to about 4600(measured this with a dial tachometer)
I disconnected the governor to see if I could slow down the rpm manually, that did not work. I am sure that the throttle plate is closing fully. I had the carburetor off of the engine and manually inspected the plate, closes all the way.
The only thing I found is that if I put something to block a hole in the throttle plate while the engine is running, the rpm goes to around 2200 rpm without the governor hooked up, which would allow me to adjust the governor speed to 3200-3600rpm.
When I uncover the hole in the throttle plate, the rpm goes back to 4600 rpm.
Do you think this is an indication of a bad carb? or should I be looking at something else?    
Any input would be greatly appreciated.
Thank you for your time
Pete


ANSWER: Is the governor vane screw or link binding?  I have had this happen before where the link or screw would bind just a little causing the RMP to be too high.

You can find the engine service manual on Toro's website.

https://homeownersolutions.toro.com/portal/server.pt/community/product_center/225#manualsResultPage

The manual covers adjusting the governor.

Let me know if the link helps.

Eric

---------- FOLLOW-UP ----------

QUESTION: Thank you for your time.
I tried to go to the website above and could not go there.
( I put the full website in the browser and would not come up)
More importantly,the answer you gave to me kinda makes sense. I say kinda because I know that the governor controls the rpm by opening and closing the throttle plate. If the governor was binding then wouldn't the throttle plate have to be
slightly open to make the engine rev? If this is true then, when the engine is running I have put a screwdriver on the throttle plate to make sure the throttle is closed. Couldn't get the rpm down until I would plug the hole in the throttle plate. Does this sign mean anything(plugging the hole in the throttle plate) Can you elaborate on this?
Thanks for your time
Pete


Answer
Go to Toro.com, then homeowner or manuals.  You can also go to "Parts" and type in your model number, 38409, to get access to the manual.

Have you checked the intake gaskets to make sure there are no air leaks in the intake system.  How were you plugging the hole?  If you plug the hole you may be causing a rich fuel mixture which would decrease the engine RPM as you are basically flooding the engine with too much fuel.  Lean conditions often cause the RPM's to increase.

Eric