In this situation you need to check that the vent orifice in the fuel tank filler cap is not clogged or stopped up. It sounds very much like this could be your problem. Unfold a paper clip or use a similar tool and poke around in the vent hole on the cap and I think you will correct the problem.

Are you still getting the same "symptom" in regard to the fuel filter appearing "un-full" when the engine dies (as before you replaced ALL these parts)? If so, the outlet port in the fuel tank may be blocked. You may have some foreign matter in your fuel tank that "floats over" and covers the outlet hole of the tank.

Yes. Still get the same result. With the engine running,I can watch the fuel get sucked out of the filter into the carb but no fuel is refilling the filter. When it sits for a while, the filter partially fills back up.

Try this: Remove the filter and replace it with a short piece of copper tubing. Same size as the ends on the filter. If this doesn't fix it--then it isn't the filter!
So many folks blame the filter because it isn't completely full of fuel at all times. But, thats the nature of fuel filters.
Try running it with the cap off the gas tank. Check the air filter for being oil soaked. If it is a paper filter--do not oil it. And, check the fuel line-the rubber part--for deterioration inside it. And, using a straightened coat hanger with a hook on one end, fish around in the tank to see if there might be something in the tank, like a piece of rag or paper, that might be floating around and getting sucked into the fuel line, before the carb.

Make sure you use a Kohler branded fuel filter that is the correct replacement for your engine. Generic filters can cause sputtering and dying on Kohler engines, especially when the engine is put under load.

Rusty's test above would help to eliminate the filter as the source as well.

The "empty filter" syndrome is quite common. Thousands of engines run just fine on them!

Did you actually observe how full the filter was BEFORE you started having problems? I'm guessing you didn't look at the filter until after the problem arose.

Machiem's advice about using the genuine Kohler filter is sound!
There are fairly rare times that a Kohler can be finicky about the filter for reasons I can't discern. Enough that I would stick with the genuine part. I'm a person that would usually buy a NAPA or similar after market filter and think it was a better/equal filter. This is a case where I wouldn't.

First let me say thank you for all of the help! I will try it without the filter but it will be a couple of days until I can get to it. Got to move the inlaws tomorrow. It does have a new Kohler fuel filter on and of course I did not observe the fuel in the filter before it was having trouble. I have tried the coat hanger but I will take a look again as I am doing everything else. I will keep you posted as to my progress. Thanks again.

With this being a Kohler engine, it might be possible that the ignition module is breaking down (or up) after starting and that the "empty filter" has nothing to do with this problem. Many times people ponder the "empty filter" when the machine is running perfectly and wonder why it is not causing problems. It is all too tempting to cite the "empty filter" as a symptom of a real problem when it might just be a red herring type of clue.

Yah, seems like an "unlikely" set of circumstances here.

IF you have access to some sort of axillary tank, even a pint size one, try disconnecting the regular tank and gravity feeding directly to the carb from the axillary tank.

I doubt you have evil spirits attaching your engine, there has to be a reason.

Walt Conner

I'm going to toss this out then shut up....

The fuel system on these machines is a closed system when fuel is in the tank and the carb float valve is closed...If air is getting into the system when the engine is running then there is a leak in the system and it will be higher than the tank so when the engine is off it does not leak but when the engine is running it sucks air not fuel.. A pin hole, loose hose joint, cracked filter case, bad seal job on a filter seam, any leak in the system anywhere above the tank level will do this and not leak fuel when the engine is not running...If the leak was below the tank level it would leak fuel when the engine is not running and suck air when the engine is running.

If the engine has a pump, the diaphragm inside it may be bad letting air from the crankcase that operates the pump into the fuel system you may also smell fuel in the oil of the engine if its bad enough.. Again if the fuel system is being sucked dry of fuel and replaced with air and the tank has fuel, there is a leak on the suction side/lines of the system....

Just my thoughts, HTH.

Bob

I beg to differ on the description of "closed system" (in regard to how this tractor is configured). There are really NO "closed systems" where a "consumable or depletable" liquid are concerned. If you comsume or deplete any of the original volumn of liquid during normal operation....you must provide a way prevent NEGATIVE PRESSURE (aka "vacuum") from developing in the system. The most often used means of preventing negative pressure from developing in the fuel tank of OPE is to simply make a hole in the top of the tank filler cap (though it may vent into a "labyrinth" chamber or baffle under the cap) to allow air to enter and replace the fuel as it is consumed. Rarely, an OEM will decide to use a "non-vented cap" and instead, will use a separate vent fixture (some of this type are even remote mounted and connected to the tank by hose). Also, IF.....the system were indeed "closed", when the engine was not running, high ambient air temperatures would pressurize the system and gasoline would escape at any leak points (pin hole, loose clamp, etc.)

mownie wrote: "you must provide a way prevent NEGATIVE PRESSURE (aka "vacuum") from developing in the system."

I say: LOL, WITH A PUMP? A pump does not work with out "NEGATIVE PRESSURE" in a system where the carb is above the tank. A pump creates a negative pressure between it and the fuel in the tank SUCKING the fuel up to the level of the PUMP. The pump has to pull the fuel UP to its level WITH "NEGATIVE PRESSURE". The tank vent allows this to happen compensating with positive pressure ON THE OTHER SIDE OF THE FUEL. The section of a fuel system between the tank and the PUMP NEGITIVE PRESSURE SIDE then to the CARB POSITIVE PRESSURE SIDE is a CLOSED system unless you open SEE there "OPEN" the float VALVE to allow fuel in or run the tank out of fuel her it comes again "OPENING" the fuel lines at the tank fitting to AIR, until then it is a CLOSED system. With the engine running the pump runs too, No fuel flows until the system is opened but the pump is pressurizing the carb, by pulling a VACUUME on the fuel in the tank.

NOW You are not wrong, on a gravity fed (positive pressure) system I would agree with you 100% that positive pressure is need through out the system for that type of system to work and until the atomization stage the system is positive. BUT not on a PUMP system there are NEGITIVE AND POSITIVE pressures evolved in all PUMP fuel systems. AND there are OPEN and CLOSED stages to these PUMP systems the FUEL it self in the tank is a valve in its own right with positive pressure on one side and negative pressure on the other when the pump is operating on a PUMP operated fuel system.

mownie wrote: "IF.....the system were indeed "closed", when the engine was not running, high ambient air temperatures would pressurize the system and gasoline would escape at any leak points (pin hole, loose clamp, etc.)"

I say: ONLY if the pressure that builds up is enough to climb back "UP" to the leak that is above the level in the tank and push out the AIR that was sucked into the CLOSED part of the system that is now open with a leak.

I STAND BY MY POST.

I would remove the tank and see how much crud is in the bottom of it. Clean it out and then work foward to the carb. Especially if the new filter is getting find rusty particles stuck in it. Now that I know the fuel system if clean and free to flow fuel I would next suspect the coil.

I would try to check for spark when the LT dies out. The theroy is the coil will heat up and quite sparking untill it cools off. Depending on conditions this could be in a few minutes to several. You can also pull the fuel line off at the carb put it in a catch can and see if fuel flow freely either by gravity fuel tank system or a cranking it over with a Pump supplied system. either way fuel should flow freely to the carb. If I was to guess based on how old the LT is would be coil. Simply part to replace, takes about 15 mins to get too and has two wires and two mount bolts, Spark plug wire and the white kill wire, just have to note the air gap (in thousands between the flywheel and coil arms.

I am amazed. This really can not be that big a deal.

A leak in the fuel line ABOVE the tank where it would suck air and not leak is not then going to allow gas into the filter when the engine is not running.

A leak in the pump diaphragm is going to fill the crankcase with gasoline and would not be sucking the filter dry.

I made a suggestion earlier. I would not recommend anyone else do this but one of the first things I would do is take a deep breath, press my mouth against the fill neck and blow. (DO NOT INHALE)

Disconnect the fuel line from the filter, put the line down low and see if fuel runs out. Something has got to be blocking the tank fuel outlet OR the fuel line is disintergenerated inside plugging off. I have also seen where fuel lines softened by ethanol collapse when pump vacuum is put on them.

Walta Conner

Atmospheric pressure (or barometric pressure) is generally stated as being 14.7 PSI (at sea level). This means that we, and ALL other objects are under the influence of a positive pressure of 14.7 PSI. A gravity fed fuel system is an "open reservoir" system in that a "vent to atmosphere" provision is required to allow atmospheric pressure to enter the tank as the fuel level drops (due to consumption by the engine). Without a vent, a head of negative pressure (vacuum) will develope in the tank above the liquid gasoline. As more fuel is consumed, this negative pressure increases and becomes so great that it equals the pull of gravity and the fuel flow stops (along with the engine). A pump fed fuel system is an "open reservoir" system in that a "vent to atmosphere" provision is required to allow atmospheric pressure to enter the tank as the fuel level drops. The fuel pump developes a negative pressure in the inlet chamber of the pump. The development of a negative pressure (or "void") allows atmospheric pressure (above the fuel in the tank) to PUSH the fuel into the inlet chamber of the pump. The pump DOES NOT "suck" the fuel through the fuel hose, the fuel is PUSHED by atmospheric pressure into the pocket of negative pressure created by the pump. Without a vent, a head of negative pressure (vacuum) will develope in the tank above the liquid gasoline. As more fuel is consumed, the negative pressure above the fuel in the tank increases until it equals the negative pressure of the pump inlet chamber and the fuel flow stops (along with the engine). The needle valve in the carburetor functions ONLY to cut off the fuel from entering the carburetor after the fuel bowl has been filled to a prescribed level (known as "float height or float level". The needle valve and float mechanism are not in any way intended to prevent "back flow" or siphoning of fuel from the float bowl. The fuel is maintained at an optimum level so that "venturi action" can feed fuel from the bowl and into the induction system (this too, is the result of atmosheric pressure above the fuel in the bowl, PUSHING the fuel into the low pressure area created in the venturi) On a gravity fed system, gravity prevents "back flow" of fuel. On a pump fed system, the inlet and outlet "check valves" prevent back flow (but only as a consequence of how they act to allow the pump to "pump". The venting provision on modern automotive gasoline systems has been modified somewhat to allow a small head of POSITIVE pressure to develope above the fuel in the tank. The pressure head forms as a result of thermal expansion of the fuel and also from partial vaporization of the fuel as it is recirculated from tank to engine and back to tank (fuel injected engines only). This positive pressure (in this case) is desired by the EPA to minimize the escape of raw fuel vapors from the tank, to the outside air. If this pressure head exceeds a certain value, the pressure is vented into a charcoal filled canister that empties into the engine air induction system. If any NEGATIVE pressure happens to develope in the tank on one of these "EPA" fuel systems, a vent opens in the filler cap to allow "compensating air" to ENTER the tank. There are no closed fuel systems handling gasoline or diesel fuel, they are ALL open systems. Only when LPG, CNG, or LNG are the fuel, do you finally come to "closed" fuel systems. Sorry!

Yep it is simple, Fuel, air, mix both, compress, (POW) or spark, POW.

Nobody can say whats wrong with out being hands on with the problem and to try is just a shot in the dark at best.

And yes with drain back from the pump, carb fuel line and filter to pump fuel line, the filter (the small one used on these engines) can refill. The air leak would not empty the line totally while the engine was running, it would just stop the fuel from being able to keep up with demand by adding bubbles (air) into the line causing a low float bowl level and the engine would die from fuel starvation. What little fuel there would be left in the pump to carb line and filter to pump line when the engine dies would drain back...to the filter being the float valve would be open at that point, thus allowing for the drain back of a half full or less line when the engine died.

IÂm with you guys..

A clog before the air leak can be the reason the air is being pulled not fuel and it can be the tank vent, BUT the air leak is still there some where before the filter (could be right at the filter inlet or the filter case seam/seal itself) for air is in the filter when the engine is running.

(A bit of a repeat) ALSO: air is seen in filters that have had air placed in them by run out of gas or the system being opened (new filter or what ever) and not purged properly leaving air trapped in the filter that is out of the fuel flow stream through the filter. This is a normal condition and is not an issue until for some reason more air is introduced forcing it into the fuel flow stream through the filter, now there are bubbles headed to the pump and carb that at low engine speeds would vent through the carb vent (letting the engine idle) but may be too much air for the engine demands at full power, and it dies. And the process goes round and round until the leak is clog removed and /or the air leak fixed.

Bob

mownie... Your right and so am I...:) SORRY TOO! Have a nice day..

Bob

mgm, thanks and you have a nice day too sir. I'm heading back outside now to "piddle" with some "honey do" items on her list :^).

If you in fact have replaced the fuel filter - and assuming that you have in fact replaced it with the correct piece.

Did you place the filter in the correct direction ? (They generally have an arrow on them telling you which way the gas flows)

OK. I'm back. Got the inlaws moved yesterday. Got out today and piddled with the LT for a few hours until I had to take a generator and supplies via flatboat to friends stranded in their flooded house. Here is what happened today. The LT cranked fine as always. I rode it around for about 5 minutes before it sputtered and died. Turned it off, waited a few minutes, cranked it again rode some more. Did this several times to see what may trigger the effect. I tried with the blade engaged and without. Lights on or off. At full speed or "cutting" speed. Not much difference in any combination. however, during one event as I was trying to get keep the engine going, it gave a large backfire and died. This was the first time it had done this. I waited again, cranked again, and took it back to the driveway. I checked the fuel tank for blockages and found none. I disconnected the fuel line from the carb and the fuel from the tank flowed freely into my container. It flowed so well it also flowed freely all over my shin, shoe, and mower deck. I then took the fuel tank and hooked it up directly to the carb without the fuel filter. I drove it around for about 15 minutes with no problem. Thinking then it "must" be the fuel filter, I reconnected the lines as normal to see if I could cause another shut off. I then drove around for another 15 or so minutes with absolutely no problems. That was when I got the call for help from our friends. Thanks "njdpo". I was wondering earlier if I had the filter on correctly. It is new Kohler filter and the arrow is pointing toward the carb. I freely admit that I am not a very mechanical person and do second guess myself frequently. Thanks again everyone.

could be you had a small piece of trash inteh line. when you disconnected it, it washed out onto you or the deck.

A little off topic here, and too late to help anyways. Just wanted to take the chance to let mownie and others know that I am going to have to leave posting in the forums to others. I will no longer be able to offer any advice or suggestions on the products I am currently familiar with. I am not at liberty to indulge into details regarding this, but will remember my short time here fondly. Keep up the good advice, mownie, you have a good head on your shoulders, and seem to attack every problem from a basic standpoint, as it should be done.

Well thanks jim98520, I've been "around the block" a few times (mechanically speaking). I've had "good mentors" (mostly because I sought them out) all my life. But I am not the most important member on this forum, there are many who have spent a lot more working hours in the OPE field than I have. I have posted some incorrect info on this forum myself (sorry about your yard), but USUALLY, the more knowledgeable, experienced members stand me up straight, and I promise not to do it again. I do this because of people like my sister, and some aunts and cousins. People who want to try saving some money by DIY. People who want to have a second or third (or more) opinion about their "ailing tractorwhatever". People who have been ripped off (or think they might have been). This forum gives folks a means of getting info and opinions that they could not purchase for any price (haha, I visited a "website" once that "was charging" for answers! Yuk, yuk....YUCK!) Sorry about whatever circumstances have led to your "censorship" (if that be it). It "chillingly" reminded me of getting "chastised" (along with one of my bosses) at work. I sent an "innocent e-mail" to "a vendor" that contracts with my employer. Well, the contact person at the "vendor" forwarded my request for technical data to his boss who forwarded it to my "boss's boss's boss". Of course, all that trickled back down and first thing I know is my boss's boss is ticked at my boss. My boss (though he knew in advance about my intent) said "I guess we better not do that anymore." I said, "I bet your right about that." You might have to come up with a "different psuedonym" (psst. don't tell anybody at work about it).

Has anyone solved this problem yet? It is happening to our mower but it is a Briggs and Stratton motor. Our small engine repair man has done just about everything for this. Please help
Thank you
Dana

I know this is an older thread, but folks like me may find it in a search so I'll post what I've done to solve it.

at first i thought it was my stator (alternator) which I changed. I've always had charging problems with the battery anyway. That didn't solve it.

Then I went to the fuel system as others here have stated. changed the fuel filter to an old part I had left from last years routine maintenance. ( I have a tendency to save perfectly good parts I change out in maintenance for just this type of occasion (it's a known good without spending money). I also loosened the fuel cap to allow an easier draw of fuel. That did the trick. No more stuttering.

Good luck to all out there and happy mowing!

My GT500 w/25hp Kohler does this same thing. I have checked the coil after it quits, and both plugs spark, I have been advised to clean the fuel cap vent (which didn't make a difference), I have replaced the fuel filter, and fuel pump as well as the breather tube. Nothing has changed the fact that it quits after about 30-45 minutes. I have taken it to 3 different repair shops and none of them can find anything wrong with it. 2 of them suggested either mowing without the fuel cap, or drilling a bigger hole in it. I am wit's end.

gunzlingr@gmail.com

I changed the head gasket and now it won't start, it cranks but won't start1

Nick88, it would really help us out a lot if you would start a new thread of your own and give a detailed description of what you are trying to work on.
Brand of engine, engine model number, why you changed the head gasket.
Based simply on the information you have posted thus far.........the correct responses might be:
You did something wrong.
You missed something.
We like to help, but we must know WHAT we are trying to help with.

fnash - yer dealing with an old thread... back in 2011 and older...