Craftsman LT4000 spitting/sputtering and backfiring after riding for 5mins

[Fish]

Wouldn't make any differences by the engine number, someone may have fitted a different carb to it, that is why I ask if it was a LMK.

I have no clue as to why you would say that. Depending on his model/spec numbers, he may or may not have adjustable valves and/or Smartspark,
which are important things to know if you want to diagnose the problems.

I would say that he just needs to adjust the valves, if he has the engine with adjustable valves.

What the heck is the problem with knowing what engine these guys have to try and give an intelligent response????

What if it has adjustable valves and Smartspark? Would that change your advice any at all?

 

[Fish]

Here is the link to the Kohler manual, I am just guessing if it is the right series, since we have no model/spec number. Heck, the picks didn't look like a Magnum.....

http://kohlerengines.com/onlinecatalog/pdf/tp_2339_d.pdf

 

[buzzpa]

I Have a Craftsman LT4000 Riding lawnmower with the kohler cv14s engine. Late in the year last year it started spitting, sputtering and backfiring then would die. It would do this after about an hour of mowing. If i tried to start it back up, it would backfire loudly. If i waited 10 mins, it would start back up and i could finish my work.

Now, it will do the exact same thing mentioned above, but it's happening more frequently, like ever 5mins!

I've changed plugs and checked the spark with a voltage meter and by placing the plug up against the engine, and it had a nice strong blue spark.

I Carried my voltage meter with me, and when it died i jump of and checked the voltage again, and everything was good.

A Mechanic told me it was the safety switches shortening out, so i disconnected all of them and it's still happening.

I Check the fuel shutoff solenoid on the bottom of the carb and touched it to the engine and the plunger worked good!

I Also removed (now replaced) the fuel shutoff solenoid with a bolt, some washers and a gasket (to make sure it wasn't faulty) and it still doing the samething.

Today, i rode it around until it started spiting and sputtering and checked the voltage on the battery, and it checked out fine.

When it starts spitting and sputtering, if i move the choke under middle ways, it will stay running without spitting and sputtering, and then i can slowly move the choke back up to the mowing position and it will run, but as soon as i engage the blade again, it will start spitting and sputter again, so i will have to disengage the blade and it will stay running half choke.

I had the same problem with my mower and had a difficult time finding the cure. ... Then I happened to see something sloshing around in the fuel tank. ... It was dried grass and I then remembered that a few weeks before I noticed that my fuel tank cap was off and that while mowing must have allowed the grass inside. ... I drained the tank and removed it to clean it out and that was the problem. ... Has been working great ever since. ... Hope this helps.

 

[EngineMan]

You never know, its time for a update on this...!

 

[ronwhite]

Sounds like the problem I had once. after about an hour of cutting it would sputter and act like it was out of gas or something. after trying lots of things, decided that the next time it happened I would stop and refill gas tank to top. that worked for me, I could fill it up and then finish my mowing. I have since removed the carb and cleaned it up good. end of problem for me.
Also had that problem when it would sputter and shut down. but those were random shutdowns but same symtoms as other problem. turned out to be ignition module.

 

[nagman]

Sounds like the problem I had once. after about an hour of cutting it would sputter and act like it was out of gas or something. after trying lots of things, decided that the next time it happened I would stop and refill gas tank to top. that worked for me, I could fill it up and then finish my mowing. I have since removed the carb and cleaned it up good. end of problem for me.
Also had that problem when it would sputter and shut down. but those were random shutdowns but same symtoms as other problem. turned out to be ignition module.

I had the same issue.

I replace the entire fuel line from the tank forward. I made sure the tank cap hole was clear. I changed the fuel filter. I changed the coil. What finally fixed it was taking the carb apart. I put the parts in an ultrasonic cleaner (Harbor Freight, cheap) and I could not believe how black the cleaning fluid got. I changed the cleaner solution twice and ran the parts through several cycles until it finished with the cleaner fluid fairly clean after the cycle. I put it all back together and it is now running great. i can only surmise that the internal passages inside the carb body were clogged up.

Hope this helps.

 

[smilinjak]

I Got to thinking this moring when i was sawing up wood and getting it busted up, if the coil is going bad, how am i able to run it for so long by just moving the throttle down just a **** hair off the the rabbit? My cousin and another guy told me that it sounds like its using up the gas faster than it should, and that the float should be laying parallel at by holding the carb at a slight angle, and barely sink into the carb when i hold the carb perfectly horizontal. Mine does neither!

Here is some images i took the other day of the carb.

View attachment 17355
View attachment 17356
View attachment 17358
View attachment 17357

With the carb off, float and needle removed blow out the inlet passage from the float side with compressed air. The dead bug that comes out will be the critter that has "bugged" you for so long. Leave your electrical test equipment in the shop, your problem is fuel starvation. If the bug doesn't solve your problem replace the fuel lines and shut off valve. I'll be watching for your results.
Smilinjak

 

[mxsmith4]

I'd agree with several of the posts here pointing to the carburetor, I had similar symptoms on my 20HP Intek and a rebuild of the carb fixed it. Also check the gas cap to see if the vent is clogged.

 

[lwrowland]

I'd agree with several of the posts here pointing to the carburetor, I had similar symptoms on my 20HP Intek and a rebuild of the carb fixed it. Also check the gas cap to see if the vent is clogged.

I would make sure the fuel filter is installed in correct direction it sounds like what I did to my generator

 

[Cimba]

Try loosening the fuel cap, leave it a bit loose and run it, bet its fine.