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

[Rebeldad1]

Sounds like fuel starvation. so......
2 things. you are either getting fuel or your not (What???)

not getting fuel..... pull the fuel line off the carb and let the fuel run into something. Should flow evenly till the tank goes empty. That's good.
if not check the inside of the tank to make sure its clean and the outlet is clear and clean. While you are at it replace the fuel line. They rot from the inside out. They can block internally and restrict flow or flat out stop it.

Getting fuel. .... several things here.
Fuel not being delivered by carb = float sticking.
Vapor lock.... several things
Engine getting too hot. Clean the head and engine of all gunk and debris. Fuel line running close to the engine causing fuel to boil in fuel line. Head gasket failure.

Take the hood off and mow see if it helps.
FUEL PM. stay away from fuel with ethanol in it.

 

[cjones636]

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

Yea it is....lol

I Just haven't messed with it during the winter due to being sick... I Would get better than would be sick again off and on throughout the whole winter. I Haven't even used the internet much... I Have an open on both end shed, and it was cold this year too! But i'm about to get out there and get with it here soon before spring and see if i can get this thing fixed. And the Carb is a LMK.

 

[EngineMan]

Well get better soon, and let us know how you get on with it...!:thumbsup:

 

[cjones636]

Since it was nice out today i removed the Ignition Coil and tested it with my multimeter. I Set it 20k OHM and it read 9.60.

 

[EngineMan]

Was that with the primary winding or the secondary...?

 

[cjones636]

Was that with the primary winding or the secondary...?

That was secondary

 

[cjones636]

Was that with the primary winding or the secondary...?

That was secondary.. The primary (i'm guessing this would be the primary).. I touched the negative to the center iron core and the positive to the kill switch tab and it didn't read, it just stayed on 1.

 

[EngineMan]

It seems that the coil is OK, then its back to the carb, because a lean mixture will also give you backfire, so recheck it.

 

[Fish]

Here is the procedure for adjusting the valve lash on the CV14 models that have adjustable valves, I would suggest you look in this area. Just take off you valve cover and look.

 

[cjones636]

It seems that the coil is OK, then its back to the carb, because a lean mixture will also give you backfire, so recheck it.

When i run the mower for 5-10 mins it's starts spitting and sputtering then it shuts down then backfires then. It will not restart until it cools down for several mins. If i run it for a few mins then manually shut it down, it doesn't backfire at all. I had another mower that would do nearly the same thing and that was getting spark. My father quickly diagnosed it as it being the coil going bad (he was a mechanic, i am not lol). He took one off an extra engine i had laying around and replaced it with the one that he said was going bad and i never had trouble out of it again. If i had an extra coil that would work on this engine, i would check and see before buying one because money is REAL tight and i want to make damn sure that it isn't the coil before blowing money on one that i did not need. I always thought that i should get a reading from the primary when i touched the negative to the center iron core, and the positive to the kill switch tab, but i didn't get a reading.. It just stayed on one (1).

My father cannot bail me out anymore when i get stumped because he had a massive stroke several years ago and he still can't move on one side of his body or speak.