I bought this Bobcat ZT (older 2005) mower with a bad carb. Replaced the carb and it worked fine for a couple mows then started puking fuel and flooding the engine.
Ordered another Nikki and installed it today. Now the engine fires right up but idles at or near WOT with the throttle against the idle stop.
I reset the gov and seems to make no difference. If I try to increase throttle off the stop, it starts bouncing off the gov.
I’m at a bit of a loss. I made sure the linkage is correct but idk what I should do about this issue.

Thanks in advance.

Here's the more detailed (long-winded) version, as my original post was posted on my phone..
I bought the mower with an issue of easy start, but would only idle.  Any throttle input resulted in popping, stumbling, and almost flooding out..  Anything off-idle was a no-go.
I noticed this had a brand new Chinesium carb on it, so I ordered another one, as I couldn't see paying more for a OEM carb than I paid for the mower.
Replaced with the new carb, and it ran like a top.  Mowed my 5ac field twice with it, and my house lawn a few times, with zero issues.
Parked it for about a week or two, went to start it, and it was a hard starter.  Took a long time cranking before it fired off, then stumbled and died.  Pulled the air filter off and there was a good bit of fuel in the throat of the intake.  Dried it all out, pulled the plugs (were wet), disconnected the fuel pump and cranked it a bit to clear out the fuel.
Cleaned the plugs up, put it all back together, and it fired off but unwillingly. 
After about 5 mins running, I shut it off for a minute to pick up some branches, and that was it; wouldn't re-fire after that.  Pulled the filter off again, and same thing.
So I ordered a Nikki clone, as well as an OEM carb rebuild kit (I got the original carb when I bought the mower).  Once here, I installed the new (#3) carb, reset the governor (throttle WOT, gov arm full CCW, and tightened everything down) and gave it a whirl..  
Things of note:  With the damper spring not connected, but all other linkages connected, the throttle sits at rest on the idle screw.  connect the damper spring, and it loads tension on the gov. rod, and pulls the throttle linkage off the stop by about 5/16".  
Start the mower, and it fires right up, then starts to climb in RPM until it's running close to full, without touching the throttle position.  If I try to move it with my finger, I'm fighting the governor tension and RPMs will only come up a little more before it starts bouncing off the limiter of the gov..
I am kinda stuck in the fact that I am not sure what to do at this point.
 

Excess fuel down the throat (from just sitting) indicated the float needle leaking / float leaking- definitly bad carb issues.  
 
Chinesium carbs are a crap shoot.  
 
I would rebuild the original carb.  
 
Also, with the engine off, the governor pushes the carb throttle to wide open.
Sounds like the governor is not adjusted correctly.  As you noted, adjust with the 
throttle wide open and the governor arm also in the wide open position. Spin the 
shaft in the same direction and tighten down..
 
If the throttle ON THE CARB is fully closed and it's still revving high, you very likely have an air leak
between the carb and head.  gasket, manifold, etc are suspect..
 
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SRTsFZ6
I would rebuild the original carb. 

Yeah, I might just do that this afternoon.

Also, with the engine off, the governor pushes the carb throttle to wide open.
Sounds like the governor is not adjusted correctly.  As you noted, adjust with the 
throttle wide open and the governor arm also in the wide open position. Spin the 
shaft in the same direction and tighten down..
 
If the throttle ON THE CARB is fully closed and it's still revving high, you very likely have an air leak
between the carb and head.  gasket, manifold, etc are suspect..
 

On the gov., I left linkage connected from gov. arm to carb, loosened the clamp bolt, used a pick to rotate the gov shaft fully CCW, then lifted the gov arm (also fully CCW to linkage allowance), and holding both, tightened the pinch bolt.  
Is that proper for baseline?
The throttle damper spring is in the hole just inboard of the linkage rod on the throttle arm, and on the gov arm, linkage in the outermost hole with the spring one hole inboard of that.

I’m such a d*****s. 😂
I adjusted the idle screw down. It was idling at about 2500 so I backed the idle stop screw down to 1250.

Thanks for the response. I was going through the items you listed and my brain clicked on finally. It’s hell get’n old. 😜

Sounds like you adjusted it correctly.  If done "backwards", the throttle won't move at all...
 
As for the spring location, if you don't know where it was, you'll have to experiment.
With that said, THE TIGHTER THE SPRING, the HIGHER THE RPMs will be..
 
Glad you figured out the high idle issue..  (S..t happens!).
 
 
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Also, on certain NIKKI carbs, besides having that weird gasket, yours may have a single,
SMALL o-ring.  If equipped, that o-ring must slip onto the plastic main piece (where the fuel would enter).
 
A touch of di-electric grease or similar would help with re-assembly as that o-ring like to roll and push out of it's spot.  Again, if applicable, that o-ring, IF MISSING would cause the carb to leak internally an not function correctly.
 
There are 2 different (slightly) styles of NIKKI's.  One will have that separate o-ring, the other won't..
Look at the parts diagram if need be..
 
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