Mower racing in neutral

[Cabrera]

I have a craftsman yts3000 with a 21hp Briggs and Stratton. It has a new spark plug, carberator, blades, oil, oil filter, air filter. The mower engine is racing when I put the mower in neutral. And when I engage the blades it sounds like a helicopter and is shaking. The butterfly is still in the carb. And the governor isn’t bent or anything. Any ideas?

 

[Scrubcadet10]

Sounds to me like the governor in the engine is no longer governing....
disconnect the linkage from the carburetor, and the governor spring from the governor arm, and manually move the throttle butterfly (throttle shaft)to increase the speed, you should see the governor arm moved towards the closed position (as it would be trying to close the throttle down since the engine is going faster)
if not, i'd be opening the engine to look at/replace the governor

 

[Richard Milhous]

If engaging the blades causes serious shaking, there's a blade or related component bent. Look for obviously deformed blades. Turn the blades 180 degrees by hand (yeah, yeah, disconnect the plug or whatever) and see if one arm of the blade come around at a different height than the other.

 

[Cabrera]

If engaging the blades causes serious shaking, there's a blade or related component bent. Look for obviously deformed blades. Turn the blades 180 degrees by hand (yeah, yeah, disconnect the plug or whatever) and see if one arm of the blade come around at a different height than the other.

The blades are fine I think it has to do with the engine not putting out enough power