I have a Kawasaki FR691V on a Toro Timecutter 5000. I am able to mow without issues until the engine randomly starts to run like it is not getting fuel. I have to turn the blades off at which time the engines idles up and down. Sometimes I have to pull the choke out just to keep it running. Other times, it will shut off entirely, and then struggles to start, and black smoke comes out of exhaust. I then continue mowing with no issues until it decides to do all of that again within 5-10 minutes or so. I can move the throttle to the middle position, and it won't do any of the above mentioned things. I removed the fuel tank and emptied all the fuel that was in it, and replaced with higher octane fuel, with Toro fuel stabilizer, changed the air filter, fuel filter, battery, and I checked both plugs and they are not fouled. It sounds like a carb issue. Does anybody have any insight into this issue. I appreciate any and all help!

Several things to check. 
 
-Loosen the fuel tank cap and try running.  If clogged, it WILL run out of gas until the tank vacuum is cleared. 
 
-I believe you have a fuel pump.  When it acts up, pull the fuel line off the carb and into a clear
container. When cranked/stating, fuel should flow into the container.  
 
-On the bottom of the carberator is a solenoid that turns fuel on and off.  It's powered by 12 volts (2 wires). When you turn the key ON, you should be able to hear/feel the solenoid CLICK.  It's function is to shut off fuel to the engine on shut down to prevent backfiring.  The  inside can seize up/fail (usually CLOSED) causing a run out of gas issue (even with a full tank).  The click is the solenoid opening-which it should do...
 
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