Problem With Cub Cadet LTX1040

Chuck (CA)

Well-known Member
I have a 19hp (Kohler) Cub Cadet that's about 3 years old. Had my share of problems; the engine rusted up with 8 hours on it. Cub OK'd the rebuild and it worked fine. Now, after it runs for about 15 or 20 minutes, it stutters and coughs, and belches blue smoke. In troubleshooting, I found that oil is coming from the tube that goes from the valve cover to the carburetor.
Any suggestions on what to look for? Thanks in advance.
 
An air cooled engine rusted up? Was it exposed to high humidity? A flood?

There may be a filter or check valve in the crankcase breather. Open it up and look, but doubtful if that is the problem with so few hours.

The oil blowing out the crankcase vent is usually caused by compression entering the crankcase. One of 2 ways, leaking rings, or blown head gasket.

If you'll remove the valve covers and rocker arms, screw an airline adapter in the plug hole, pressure up the cylinders, you'll be able to hear where the leak is.

If it's blowing out the head gasket, you'll feel it, hear it blowing in the pushrod area.

If it's going deeper, it's rings. Some ring leakage is normal, just a small hiss is acceptable.
 
Blowing blue smoke, I would check the oil. Both for being over the full mark and for gasoline in the oil.

You don"t say what engine it is. Is it a Courage or a Command series engine?
 
I'm assuming the blue smoke is the result of the oil in the tube going into the carb. The engine is a Courage.
 
The company went so far as to check the winter weather prior to the engine rust issue. (It was a dry Winter). I will admit that I pressure washed the tractor as I do with my 10 year old Craftsman with the B/S engine which has never given me a problem engine wise. I will get one of those adapters, but will a compression tester help pinpoint the problem?
 
A compression test will give some idea, but only if one cylinder is checking lower than the other. If the problem is with one cylinder, that will show as poor idle.

The rust... What happened there? The engine stuck? Rings stuck? Was it disassembled?
 
I don't have an answer regarding the rust. The reason I took it in originally was it turned over very slow and would not fire. (I thought it was the starter.)
I have a pressure washer with a Kohler, and I gotta say, I'm not impressed. The washer is sometimes temperamental to start.
Anyway, I have to go to town today, so I'll get that airhose adapter and see what that tells me.
BTW, I pulled the oil tube from the aircleaner, and it ran fine, but the oil just got sucked onto the exhaust and of course it smoked like a chimney.
 
Yes, the blue smoke is oil going from the crankcase breather through the carburetor and from there back through the engine.

Your problem is either: The rings not seating,which lets combustion pressurize the crankcase and forcing the oil out. Or:

The crankcase breather valve is not doing its job, either broken of bent. (Its in the valve cover near where that hose comes out. I think you have to replace the valve cover if it is bad.) The crankcase breather valve is supposed to maintain a slight vacum in the crankcase at all times and can do so unless there is too much combustion gas getting into the crankcase. Or:

There is also the possibility of a blown head gasket. If the gasket is blown into the pushrod area, combustion can enter the crankcase that way. Or:

There is no drain back hole in the head or in the block for the oil that comes past the tappets to get back to the crankcase. So it pools up and goes through the breather valve into the carburetor. I have seen this on one single cylinder Courage engine. In that case they just failed to drill the hole in the head.
 

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