I have a John Deere GX345 with a Kawasaki liquid cooled 20HP engine. Start the tractor up and it runs fine. Start running the tractor and within a couple of minutes it starts what seems like the motor is misfiring. It almost seems like water in the fuel. I drained the carb and fuel pump, pulled the tank and flushed adding new fuel, replaced the fuel lines from the tank to the fuel pump and cleaned the plugs. When I pulled the plugs it is running very rich (black appearance) on the one cylinder. The tractor has approx 210 hours on it. Any ideas?

you need valve job done and new valves put in and i said new valves do not use old valves again 150.00 per cylinder

look underneath did drive belt snap in two , rear has white plastic fan on top of it that should be rotating with engine running if not yep you broke a belt , don't know about wire could it be from front PTO they are electric so it will need a wire ,one possibility is that drive belt broke slapped front PTO and broke off wire , that musta been some snow your pushin ooh and a reminder never push a hydrostatic drive tractor without pump turning it will dammage it

Drain fuel completely from tank, fuel line, and carburetor... Change fuel filter, change spark plug(s) add FRESH gas... Not 1 week, month or year old gas... (Can't be contaminated, or mixed with old fuel) there will be a drain screw on the carburetor (at the side of the bowl) You may need some quick start to get the engine to initially start up and keep it running with the spray until the fuel system fills up with fresh fuel and stays started.

recheck your jets also check the needle valve seat they swell up and stop fuel flow next replace the solenoid with a short bolt and try that they might sound as they are working but don't

need new coil pack or have short in harness grounding engine from running. check fuel line to carburator. 1. take float bowel off bottom of carb. do not touch float or pin holding float. crank engine over until fuel comes out of carb. If fuel comes out, you don't have fuel problem. put float bowel back on carb. 2. check for spark. take spark plug out of mower. put wire back on plug and place the threads on head [or metal of engine to ground the plug]. crank engine over for a few seconds to see if plug gets spark . [always double check with another spark plug that is good]. [[ Remember!!! you have to have someone sitting on the lawnmower to start. unless you by-pass safety switch [only do this if you understand how the safety switch works. NOT EXPLAINED HERE!!!]] If spark is present, there is no grounding problem. when engine is cool. 3. CHECK COIL PACK. for continuity. When the coil pack gets hot it will stop any juice to the plug. A>Check temp sensor B> Check Safety switches grounding out. C> Check for cut wiring harnes. [loose wires rubbing against pulleys, wires cut by rodents]. Hope this helps.........................GAS

Water pump gear or the water pump impeller could have failed. If its the pump and due to it being at the bottom front side of the engine it would take some time for it to boil due to the fan is always pulling air down thru the radiator and its at the very top of engine. Cool water on top and really hot coolant around the cylinder with sensor. I'm sure it's the pump.

more then likely has faulty coil on one cylinder

Try adjusting the deck height up a little or start a the carb.

You have dirt in the fuel tank and it sucks the dirt up on the filter that is attached to the pump. After the machine stalls, the dirt falls off and it will restart and run for a few min.