My yard machine will not shut off after i let go of throttle

Do you have the engine at full throttle.

Perhaps it's set at too lower speed when starting off. Just increase throttle speed to take up the load when engaging PTO. I gather it's a 2 speed PTO. Sometimes they need higher revs to function trouble free.

try you-tube so many great videos to get you going again.

need carb throttle adjustment about 20.00

Are you saying that it surges at full throttle and wont idle down or shut off? If so it is likely not a governor problem. Surging is a lean condition. Some models, particularly yard machines, will surge no matter the adjustment unless under a load. If it were a governor issue it would run faster and faster beyond full throttle. IF it wont idle down check the throttle control and throttle linkage and check for a sticking throttle shaft before suspecting governor. Not shutting off could also be in the throttle control. A ground clip is in the control. if the tab is not engaging the clip or the wire is not connected then the motor will not ground. Check those things before messing with the governor, especially if the machine was running good and no one has messed with it yet. Governors don't just come out of adjustment by themselves.

Check the shut off switch

that wire needs to be conected

The ignition switch probably has a short in it , I would have it checked at a shop . They shouldnt charge to check it . Good luck

Did you clean out the carburetor jet? It is the brass screw that holds the bowl on the carburetor. Use a piece of wire and some carb cleaner to clean it out. Do not use a drill to clean it out!
Good day.

Most newer models do not have a throttle, but you can rev it up a bit, by finding the governor rod and spring and pulling it.