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I recently rebuilt the carb in this 19.5hp OT (42E707-2631-E3)... I have plenty of trouble with this. Finally rewired it without all the safety switches. And got it running. Except now, when I turn too sharp too fast, it tries to stall. I have to choke it all the time. By the time I was finished mowing (about 7acres) the choke was all the way out. I could push in the choke and back out real fast and it would almost die, but rev up even higher than before...
Also, when idling, it revs up and down constantly..

hrdman2luv said:

I recently rebuilt the carb in this 19.5hp OT (42E707-2631-E3)... I have plenty of trouble with this. Finally rewired it without all the safety switches. And got it running. Except now, when I turn too sharp too fast, it tries to stall. I have to choke it all the time. By the time I was finished mowing (about 7acres) the choke was all the way out. I could push in the choke and back out real fast and it would almost die, but rev up even higher than before...
Also, when idling, it revs up and down constantly..

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You have an air leak in the induction system, or a blockage in the fuel system, or a dud fuel pump.
it is a process of elimination,

Fuel pump - put some fuel in a container with a length of fuel line attached to it ( pinch the one off your push mower ), support it about 1 foot or more above the engine & fire the motor up.
If it runs substantially better then the fuel pump needs a service. The units on the twins tend to give a bit of trouble.

Air leak, with the engine running as slow as you can get it to with the least amount of choke put some WD 40 in a trigger bottle DO NOT USE A PRESSURE CAN and spray a jet of WD40 all around the joints including the butterfly pivots.
If there is a leak it will be most obvious

I find that the most common cause of engine surging is a carb that needs to be cleaned and rebuilt. Usually find that the float is set to low, causing a lean mixture.