# Craftsman DYT 4000 24hp Kohler - Hitting on One Cylinder



## gallowayb (Apr 20, 2010)

I have a Craftsman DYT 4000 with about 220 hours on it and on Friday it was running fine. On Sunday I had my son move it to get to the ATV. I heard the mower and it sounded terrible. I started it today and it sounds like it is running on one cylinder. There is spark to the non-firing side and the plug looked OK. I touched the exhaust on the non-firing side and it was cool. I'm guessing fuel starvation to the one cylinder. I used some 4 stroke carb cleaner (worked great on my Johnson outboard!) but the one cylinder will not fire. I can guarantee there's a spark, there's air, but I don't think there is fuel.

Has anyone had a similar problem? Is the solution to pull the carb and have it cleaned/rebuilt? I'm sort of handy, but time is not very plentiful these days.

Of note: the air filter was dirty. I cleaned the element and did my best to knock dust from the filter. Mower still only hit on 1 with the filter completely off.

Oil: it was low, just below the add mark. Stupid move to let it get down and not have changed it. I topped it off.

I really like the mower. It does a good job on my couple of acres.


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## Live Oak (Dec 22, 2003)

Welcome to Tractor Forum gallowayb! Have you done a compression check on the non-firing cylinder?


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## gallowayb (Apr 20, 2010)

Hey there, thanks for the response.

No, I have not done the compression check. I don't have the equipment to do that. I am starting to suspect a problem in that cylinder though. Not sure if there's a ring broken or something more sinister.

The carb looks clean and since it is a single carb it feeds both sides, it wouldn't be the cause of one running fine and one not firing at all. I'll see if I can see anything in the cylinder via the spark plug hole. If that doesn't reveal anything, I'll put it back together and swap the spark plugs around. If that's a no-go, then I'll probably trailer it to a small engine repair guy and see what's up next.

I don't see myself having the time to pull the head and do rings or replace a piston. I've got concrete work this week and will be lucky to find a minute outside of my real job and the extra-carriculars...

Thanks,
Barry


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## Live Oak (Dec 22, 2003)

Barry, this could be something as simple as a stuck valve. I have had this happen to me a number of times after some of my small gas engines and ATV's have set up over the winter months. 

Try removing the valve cover on the bad cylinder and have a look at the valves to ensure they are getting full up and down movement during each cycle turning the engine over slowly (with the ignition disabled). 

If the valve is stuck and NOT BENT, you may be able to manually work the stuck valve up and down a few times to free it up. This happened to me on my Honda engines a few times.


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## gallowayb (Apr 20, 2010)

I have put about 8 hours on the mower this Spring and am on the 2nd tank of fuel. I put the mower away and it sat at least overnight if not two nights before the problem started two days ago. Hopefully we're looking at a stuck valve and I can get the thing un-stuck.
Thanks again,
Barry


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## Live Oak (Dec 22, 2003)

Good luck and be sure to post your results. Hopefully, you can fix it and someone else can benefit from your experience.


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## gallowayb (Apr 20, 2010)

The results are in: Stuck valve

I pulled the valve cover and found a bent pushrod. I noticed how little travel there was on the one valve (the smaller diameter of the two). I got a wooden dowel and a hammer and tried to tap it loose with no luck. I pulled the head and noticed that there was some travel on the valve and saw the holder was pushed out nearly a half inch. I dissasembled the valve and got a wood block and tapped the valve guide back flush to match the other. I reassembled everything and the valves have equal travel. My plan is to order new pushrods, new gaskets, and a new valve. I think that will do it!


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## Live Oak (Dec 22, 2003)

If you have the time and a camera, some pics of this would prove very interesting. It would be interesting to see or find out just what caused this.


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## gallowayb (Apr 20, 2010)

I ordered new pushrods and gaskets and should be ready for the check ride on Friday or Saturday.

An interesting note: Sears Parts Direct was showing the head/valve package as backordered on the 5A side (the other cylinder is 5). This tells me that the 5A side might be the proverbial Canary in the Coal Mine for low oil, or the weakest link. The 5A side is sold out, the 5 side is in stock.

If I get some time I may be able to snap some pictures of the damage and reassembly.

-Barry


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## Live Oak (Dec 22, 2003)

Sadly, it appears that they just don't make small engines like they used to. I try to stick with Honda small engines whenever possible now adays. They seem to be the most reliable and long lasting. 

Thanks for the follow up comments and info. Barry.


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