Kabota Z726X starts, but dies

[jj50cal``]

hi folks, my Z726X starts easily, and runs great for about 30 minutes. then act like it is running out of fuel. but it's full, checked and changed fuel filter, checked, cleaned fuel pump, then replaced said pump, replaced all fuel lines. after it sits and cools off for about 20 minutes, you can get another 10 minutes of run time. if you let it cool down till cold, you get another 30 minutes. air filters are clean and new also.i even had an extra set of coils O.E.M. coils checked good, but swapped out anyway since they were availible, and no difference. HELP! i have too much yard to mow in 30 min. increments.

 

[bertsmobile1]

The instant it stops spray a little carb cleaner down the carb & crank the engine.
If it fires then you have a fuel delivery problem
If it does not fire it is an electrical /valve problem
Let us know what happens for more details

 

[jj50cal``]

ooookay, sorry it has taken me so long to get back, but , here goes.. ran it again, got 20 minutes of mow time, and realized i can turn off blade clutch, and hurrily put it in neutral and lock the brake and it will continue to run. if i let it do this for about 5 minutes i can get back on and get another 10 to 15 minutes of mow time. i repeated this maneuver about 5 times, each time i checked for leaks, (fuel, vacuum,). did notice the fuel filter was not full and appeared to have about a 1/6 of inch air gap at the outlet going towards vacuum fuel pump. have not had opportunity to purchase starting fluid yet.

 

[lugbolt]

On the top of the fuel tank there's a shutoff valve. Remove the fuel line from the valve. Then yank on the valve, it just pulls out of the tank. Now that the valve is out, you can take a look see. Does the valve have a screen on the end? If so, you have the new style valve, so put it back in after cleaning the junk out of the fuel tank. If no screen, run to your nearest Kubota dealer and grab a new shutoff valve assembly that does have the valve. Solves the problem.

The problem is, the valve itself has a tube that runs down into the tank (pickup tube)-then the fuel line comes out & goes to the motor. The junction of the two is a sharp 90 degree turn, so any junk in the fuel tank is GOING to get into the sharp turn and plugs up the passage. Then usually it'll run a while, die off, sometimes dies altogether. Try again after sitting, some of the junk settles out and it'll run-until it sucks up more junk and plugs the passage. Thats why kubota redesigned them with a screen on the tip of the pickup tube.

When you pull the tube out of the tank it'd be advsable to do it with less than 1/2 tank of fuel. A full tank will gush about 1/4 of the gas out when you remove the pickup tube.....speaking from experience, it makes a huge mess and a fire hazard.