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The mower starts and runs great but after a few minutes it will die and then after a few minutes it will start back up, and sometimes it will continue to run for a period of time and then shut down. I check the fuel and add some and it will start and run for a while.The fuel tank is never empty. I have serviced the Kohler KT725 engine with a new air and fuel filter and changed the spark plugs and nothing changes. I have never seen the fuel tank empty and I am wondering if the kohler vacuum fuel pump does not have enough power to pick up from the fuel tank.

I need some help

Thanks
Jerry

https://kohlerpower.com/en/engines/manuals

click on above & enter KT725, scroll down page & your engine service manual will appear, click on service manual & see page 24 troubleshooting. i believe you have stale fuel in gas tank, add a quality brand fuel treatment & fresh high test gas, let us know how it goes. have you changed oil & filter recently? not mentioned in your post.

It's possible that your fuel tank isn't venting or that you have a bad ignition coil.

Yes I agree with Darryl loosen your fuel cap and let it run on a dust free surface.......

Sounds like you are starting and running your bowl dry. Then itis filling back up then it does it again. So plugged fuel line or fuel tank. Could also be a bad fuel pump.

You can rule out the tank & tank vent simply by removing the fuel line at the pump (from the tank).

Let gravity empty the tank into another container.

If it stops flowing you have an issue with the cap/tank, etc.

If it flows fully, move on to the fuel pump.


Coils do fail, often once hot. When the engine starts acting up, pull plug wires & test for spark (spare known good plug).
If no spark, you have a bad coil..

Darryl G said:

It's possible that your fuel tank isn't venting or that you have a bad ignition coil.

Click to expand...

I have checked the vent and hose from the air cleaner and they are open and venting. The engine when it stops, stops immediately which doesn't seem to be a coil or it would misfire before it stopped.

Thank you for your suggestion.

Jerry.

mechanic mark said:

https://kohlerpower.com/en/engines/manuals

click on above & enter KT725, scroll down page & your engine service manual will appear, click on service manual & see page 24 troubleshooting. i believe you have stale fuel in gas tank, add a quality brand fuel treatment & fresh high test gas, let us know how it goes. have you changed oil & filter recently? not mentioned in your post.

Click to expand...

I have changed the oil and oil filter and I use a 10-30W synthetic oil and I use stabul gas treatment.

Boudreaux In Eunice La. said:

Yes I agree with Darryl loosen your fuel cap and let it run on a dust free surface.......

Click to expand...

I have loosened the fuel cap and it does not seem to help, but do you know or have knowledge to a way to test the large fuel cap on the toro.

Thank you for your suggestion

Jerry.

With you letting us know it stops mediately kind of leads me to believe it's a safety switch. I would clean them with some electric contact cleaner. And then see if it continues to happen.

JerryL said:

The engine when it stops, stops immediately which doesn't seem to be a coil or it would misfire before it stopped.
.

Click to expand...

If the coil fails/stops firing, it can't misfire, there's no spark..

The safety switches(as noted above), kills the ignition(if running)-NO SPARK...

OK, we need to determine if it is an electrical or fuel problem.
So remove the blower housing and remove the kill wires from the coils.
Start the engine then shut it off a few times.
If the engine shuts down every time, then you know that the fuel solenoid is working.
Replace the blower housing then go mow.
Be extra careful as all of the safety circuits run off the kill wires.
If the problem goes away then you have a problem with the mowers wiring, let us know & we will walk you through finding the fault.

If the problem continues replace the kill wires then remove the fuel shut off solenoid on the carb & replace it with a short bolt.
Check that the mower shuts down when you turn it off then go mow.
Problem goes away you have a fault with the solenoid or the wiring to it, this is very common.

If the problem persists then find a replacement fuel tank.
You should be able to get one from a mower repair shop ( not a glass front retail store ).
Hook it up and go mow.
Try it both direct to the carb and also to the fuel pump
Problem goes away then you have a fuel supply problem.
Could be bad lines or debris blocking the fuel tank outlet.

Problem persists then you have an internal engine problem or blockage in the exhaust.

I had to give up and take the mower to a warranty Dealer. The problem with the mower was that the Kohler engine oil pressure switch was faulty, also their was a
blockage between my main fuel tank and the poney tank . The problems were addressed and the mower works great.

jerryl

Not the 1st time I've heard of a bad Kohler oil pressure switch.

PS That Sta-Bil you use has limited life to it. It is 2 years on the bottle once opened. It gets gummy after that.

Seafoam is my fav. Stabilized gas for 2 years, & the bottle after opening can stay on the shelf for 50 years & still be good.

Using 100% gas is a big plus also.

Enjoy !!