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Hi Folks.......I have a Fd501V_-Aso1 Kawasaki engine in this mower. It has a brand new 300dollar Carb on it. It will mow 30 min or so and dies. It will crank again and then die over and over. In 30 minutes or so it will crank and run. Any suggestions out there. It also has new plugs....air filter and gas filter as well. I am puzzled what to look for . Please help! Thanks in advance! Judy

Sometimes the seat safety switch will intermittently cut out if you go over a big enough bump and kill the engine but it could be lots of things. Next time it dies try loosening the fuel tank cap and see if that helps.

Lawnranger said:

Sometimes the seat safety switch will intermittently cut out if you go over a big enough bump and kill the engine but it could be lots of things. Next time it dies try loosening the fuel tank cap and see if that helps.

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I thank you very much for getting back so promptly....Lawnranger....I have tried the gas cap loosening.....that doesnt work. Can you or someone else think of anything else for me to check?

An engine needs three things to operate properly: correct air/fuel ratio, sufficient spark at the right time and compression. It sounds like one of the above is intermittently missing from the picture and intermittent problems are the most difficult to find.

If I am understanding your original post correctly, it sounds like the mower will work just fine for 30 minutes and then die. When you attempt to restart the engine it will run for a moment and die again with this process repeating itself until you let it cool down for 30 minutes and then it will run just fine for another 30 minutes. Is this correct? If so, I would check for spark while the problem is evident. It is possible that the ignition coil is heating up and going open while hot and when it cools down it will work again. A bad coil is not the most common problem but it does happen from time to time.

Since the engine runs well for a period of 30 minutes and then dies, it leads me to believe that it is spark or fuel related. However, a sticking valve could cause a loss of compression and then free up after it cools down causing the symptom you describe. As I already stated, one of the three factors is missing and you are the eyes & hands of the situation which means you will have to do the work to find out what is missing.

Make the problem happen and check for spark first as it's the simplest system to check. If the spark is good then spray a shot of carburetor cleaner directly into the carburetor (air filter removed) and try to start it using carburetor cleaner as the fuel.

Thank You......You described the situation perfectly.....it is also trying to surge on me before dies.....but when it runs ..it runs good!! i have some carb cleaner ...will try that.:smile:

Ok....when it got cool enough outside to look at it ....heres what I did ....removed air filter and screen guard on top of radiator ( i ran it til it died then removed filter)....shot it with carb cleaner....it cranked right up but surging 2 times every 3 or 4 seconds. It died after about 5 minutes or so with deck engaged. Put everything back together...cranked it and it ran somewhat normal for about 6 or 7 mins. I mowed maybe 50 sq feet.....then it dies. I guess I will remove the outer covers tomorrow and check the carb bowl for debris......With a new carb on this puppy......I just cant believe it!!!!! Anything else I need to check while I have the covers off? Thanks ....Judy

JDMATT said:

Ok....when it got cool enough outside to look at it ....heres what I did ....removed air filter and screen guard on top of radiator ( i ran it til it died then removed filter)....shot it with carb cleaner....it cranked right up but surging 2 times every 3 or 4 seconds. It died after about 5 minutes or so with deck engaged. Put everything back together...cranked it and it ran somewhat normal for about 6 or 7 mins. I mowed maybe 50 sq feet.....then it dies. I guess I will remove the outer covers tomorrow and check the carb bowl for debris......With a new carb on this puppy......I just cant believe it!!!!! Anything else I need to check while I have the covers off? Thanks ....Judy

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Are these symptoms the same as before you replaced the carburetor or has something new surfaced?

After I replaced the carb it ran like a champ.....I mowed 1/2 acre 2 or 3 times with no problem......then back to the same thing before I replaced the carb. Yes the symtoms were the same before the new carb.

I went back and reread all the posts and the fact that the engine is surging raised a red flag.

I have a few questions I'd like you to answer.

What is the age of the mower?

When it does run, how well does it run?

Does it surge just before it starts to act like it is going to die?

Did any new symptoms appear after you replaced the carburetor?

Did you alter anything on the mower?

Any chance the fuel you are using has gone bad? How fresh is the fuel you are using?

Anything more you can tell me?

It is a 1998 model.....when it runs good ..yes it runs good.....Yes it may surge for 3 or 4 moments before dying...and sometime no surge ..it just dies.........no new symtoms.. doing the same thing I have not altered anything on the mower at all.......I drained the gas tank and checked for debris with the first set of probs before I replaced the carb. The first carb began to leak so that why I bought a new one.....It has Fresh Gas..... When fuel pump goes out....doesnt it just go OUT? It doesnt go out gradually does it? I have checked the fuel pump it is feeding the carb. Got me buffaloed.......:smile:

I'm trying to determine if this is a fuel problem or spark problem and the symptoms can indicate either one. Many times when an engine is running out of gas (lean) it will surge and sometimes pop (backfire) due to running lean. I'd really like to see an inline spark checker hooked up while the problem is happening.

Have you replaced the fuel lines? I have seen where fuel lines soften and squeeze together shutting off fuel flow to the carburetor and this can cause an engine to surge then die. I have also seen an obstruction in the fuel line cause similar symptoms. The list can go on for a long time and I don't want to recommend a part change without proof that it failed. A 14 year old mower could have something bouncing off the bottom of the fuel tank such as a leaf that will intermittently plug the fuel tank outlet. There are so many possibilities in a case like this and until you can pinpoint something it is just speculation.

Until we determine what factor is missing when the engine acts up it is going to be a shot in the dark checking all the systems on the mower for the actual problem.

The fuel pump has an impulse line that connects to the engine. Find the line that is not one of the two fuel lines and check it carefully for leakage of any kind. This line provides the fuel pump with alternating vacuum/pressure to operate the fuel pump. If there is a weak spot in the line it could collapse which would cause the pump to not pump fuel. Again, I'm offering possible causes but you will have to check all these items to verify if they pass or fail.

I'll keep thinking on this one and if anything else comes to mind I'll make sure to post it here.

Thanks dearly for sticking with me on this.....Hopefully ...I have not been silly enuff to let such as a leaf get in my fuel tank.....will know more tomorrow...hopefully......altho I am having a few beers tonite as I am disgusted with this mess. I will check fuel pump line as you said. I have always done all repairs on this mower myself since I have had it and its been a good machine......its just that this prob has me stumped at this point. I have faith we will figure this out!!:smile: Thanks for sticking wih me on this!! Judy

A foreign object finding its way into your gas tank is possible but not your fault. I was filling my generator after a hurricane wiped out the power lines and I was using a funnel so I wouldn't spill any fuel when a large insect flew into the funnel and the stream of gasoline washed it down before I could stop pouring from the 5 gallon jug. It happens.

Lawnranger.....it was 100 degrees ouside today and way to hot for me to work my mower today......Have you thought of anything new for me to check? Maybe someone else out there has had this problem...all suggestions are appreciated!!!

JDMATT said:

Lawnranger.....it was 100 degrees ouside today and way to hot for me to work my mower today......Have you thought of anything new for me to check? Maybe someone else out there has had this problem...all suggestions are appreciated!!!

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Yeah, I know it was 100 degrees today - I worked outside all day

Perform the checks I posted previously and let me know what you find.

I tried to check the safety switch under the seat yesterday and couldnt unplug it....I assume it unplugs..... looks like a terminal plug with two wires....I was afraid to put pliers on it....Its plastic and I was afraid I would break it and have another problem. Is there atrick to unplugging it?

Sometimes there are "locks" on the side of the connector and you have to use a small screwdriver to spread the lock open and then you can slide the connectors apart. How bout the other checks-the impulse line?

I havent pulled the covers off yet so I can see the fuel pump....I dont remember seeing a third hose on it but I wasnt looking for one either....that very well could be the problem. I have not replaced a lot of hoses on that mower....I bought it new. Its a one owner..me. Sorry you had to work in the heat....I am too old to work in it. If I had a stroke ..it would be 3 weeks before someone found me. That safety button terminal is kinda hidden under the frame ..should I put the pliers to it and tug gently?

I feel too old to be working in this heat but I do it anyway. Hehe.

The safety switch - hmmmm. Don't you just love how the engineers design some things. I jokingly say that they get the best drugs. Some of the stuff they dream up really makes me shake my head but I realize it's not always the engineers fault, it's the bean counter. You can try with a pliers but be gentle. If it doesn't come apart easily I'd try from underneath or if there are screws holding the switch in place, remove them and maybe you can get to the connector. I have several ways of lifting riding mowers and one of them is with an engine hoist connected to the front or rear of the mower and this helps me gain access the the underside of the mower. Do you have access to an engine hoist?

Nope... no hoist and hopefully I wont need one for this problem I have. Does a fuel pump go out gradually or suddenly stop working on the average? When it cools down outside I am going to at least pull the covers off this evening so I can see the carb and fuel pump.

A fuel pump can go out either way you describe as it depends on what caused the failure. I have had a fuel pump diaphragm stick to the body of the pump and cease to work all at once and then I've seen the impulse line start to soften and gradually cause problems. I'm sure there are other causes of fuel pump failure and a hole in the diaphragm is another possibility. You just have to start checking the basics and branch out from there. Like I said, an engine needs the proper air/fuel ratio, sufficient spark at the right time and good compression to operate and we'll have to find out which one is missing and in what proportion. Look at it as a game of hide and seek.

These machines, and I'm referring to all outdoor power equipment, can be challenging to diagnose as some of the symptoms can be caused by the same failure. For instance, I had a push mower in today and it had no spark so I pulled the small kill wire off the coil and I had spark so I checked where the other end of the wire connects to the cable controlled kill switch and the switch was not opening far enough to break contact so I adjusted the cable and put everything back together. Guess what? No spark. So I checked everything again and found the kill wire insulation was rubbed through shorting to ground. Go figure. If I checked the wire first I would have found the insulation rub through and thought to myself I had it fixed but then I would still have no spark until I adjusted the cable. It's things like this that keep my mind open to more possibilities.

You have to think like a detective and look for all possible causes and sometimes the impossible causes because the mind will not always let a person think outside the box. I may be on the right track in helping you and I may be way, way off course but I don't want to rule out anything until it's verified. Whether it's me or someone else who helps you, eventually your problem will get solved.

I pulled the cover off and looked at the fuel pump closely....I only see two hoses one from the gas tank and the other to the carb...two nuts attaching it to the engine. Is that normal? I also looked at the safety switch...it has two little locks underneath ...I think. I also discovered the gas filter wasnt clamped on one side...the side going to the pump.....could that have anything to do with the prob....it didnt seem to be leaking gas there though.

Well I went to partstree to see a diagram of your engine and it appears you have a mechanical fuel pump and this type of pump usually has only two hoses. Back in the day we used to test automotive fuel pumps of the same design with a low pressure fuel pump gauge and you may have to do the same or have it tested. Another fuel pump test is a volume test - again you may want to have someone test this for you. I think it would be wise to test the capability of your fuel pump just to make sure it is not causing any problems.

The missing clamp obviously was not a problem but you certainly want to clamp in now that you know it was missing. Probably not the cause of your problem though.

Ok heres the latest update......I went out early this morning...cranked it up and mowed about 10-15 min and it surged and died.....I noticed the temerature light was on....I let it cool down and added about a picther of water......I also took the carb bowl off the bottom...it was full of gas but very CLEAN (tells me the pump is working ok)....I pushed the float up and let it drop about 4 or 5 times.....put the bowl back on. I then cranked it up and mowed the whole yard (1/4 acre) It never surged or died again. I parked it rushed in the house to write Lawnranger and the forum. Maybe a stuck needle in the carb??? This evening I will clean the top and bottom of the deck....Grass was pretty wet!! Any ideas or does my Kubota have a mind of its own....like my computer? My horses mind better than my mower!!!! Thanks loads for your help. Lawnranger ....in the future if I have probs... is there any way to talk to you direct thru the forum?....You are a very smart fellow with Lawn Tractors!!!

A stuck needle in the carburetor can definitely cause the problem you are describing. However, you have a brand new $300.00 carburetor on your tractor and why would the new carburetor have the exact same symptom as the old one? Hopefully you found the problem but I'm cautiously optimistic and the reason is why would the float stick in the first place? I'd feel much better about replacing a part when i can be certain that it failed but in your case we can't find the failed part.....yet.

Thank you for the kind words. I have been working on small engines/automobiles/equipment for almost four decades and have seen a lot but certainly not everything. I just can't recommend spending someone's money until I can pinpoint the problem and in your case we still don't know for sure what the problem is/was. There is an old proverb that goes like this: "As iron sharpens iron, so one man sharpens another". I sure don't know it all and I come here to get "sharpened" as well as helping "sharpen" others. I believe there is a feature of this forum called "private messages" and maybe through the "notification" button at the top right of the screen you will be able to send me a private message.

Gents, I'm having the exactly same issue in Auz, was JDMATT's issue resolved?

JDMATT said:

Ok heres the latest update......I went out early this morning...cranked it up and mowed about 10-15 min and it surged and died.....I noticed the temerature light was on....I let it cool down and added about a picther of water

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Normally when an engine surges and dies, that happens as you run out of fuel, or fuel is restricted. Have you checked your fuel cap to make sure it is venting? If you can catch it just before it dies, then if you loosen the fuel cap soon enough, and if "that" was your problem, it should start running normally again. Another subject of concern is "why" you needed to add a pitcher of water after cooling down. Was it overheating?