Kohler Command CV25 – white smoke on startup.

[clempot911]

I have had this tractor, a Craftsman GT3000, for the last 8 years, and, on and off, to some degree it has always blown white/gray smoke on start up. Sometimes it’s just a little, other times it’s like a cloud. When it was still under warranty I had Sears come up and look at it and, just like a car at the dealer, the thing started right up no smoke to be found. The next time I go to cut the lawn...smoke cloud.

I checked compression a few times, the numbers seemed to be reasonable (150 or so, if I remember correctly). It’s not overfilled with oil, and the air and pre-filter are clean/new. It now has about 180 hours on it. I have tried starting it up with the breather tube disconnected - the tube that goes to the oil separator to the air cleaner, no difference so, if it’s oil, it’s not coming from there. At some point I also removed one of the valve covers and found there was perhaps 1/4” or so of oil in there – I don’t know if that’s normal or not.

I have read that these engines are very susceptible to blowing head gaskets, but it seems like the compression numbers and no lack of power would indicate that's not my problem. I also found some info stating that some of these engines were known to smoke on start up and Kohler redesigned the piston (something to do with decreasing an oil hole) to fix this. I find it hard to believe that this is the problem on mine, how would that ever get past quality control?

Anyways, I’d appreciate any ideas.
Thanks

[GlenM]

I have a 1997 Sears GT with this same motor, Got it with 400+ hrs on it. Does the same thing, Lotsa white smoke on startup.
Clears up after 3-5 secs. Starts good, runs and cuts good. Oil up to mark with stick not screwed in.
would be interested in cause.
thanks,

[AllSeasons]

Since these engines are air cooled you can rule out water in the cylinder. Are you sure it doesn't have a tinge of blue to the color? You are most likely leaking a little oil past the valve guides. You will still get good compression because if the valves are working right it seals the compression chamber on the compression stroke. Once oil leaks past the valve guide it just sits and waits for the intake valve to open and suck it into the chamber. Once it fires it burns the oil giving you the smoke. Dirt oil or dirty air intake will cause enough damage to a guide to cause a leak. The reason that they quit smoking after start up is because there isn't enough oil introduced into the cylinder on each intake valve opening, only after it sits and collects for a while.

[clempot911]

Since these engines are air cooled you can rule out water in the cylinder. Are you sure it doesn't have a tinge of blue to the color? You are most likely leaking a little oil past the valve guides. You will still get good compression because if the valves are working right it seals the compression chamber on the compression stroke. Once oil leaks past the valve guide it just sits and waits for the intake valve to open and suck it into the chamber. Once it fires it burns the oil giving you the smoke. Dirt oil or dirty air intake will cause enough damage to a guide to cause a leak. The reason that they quit smoking after start up is because there isn't enough oil introduced into the cylinder on each intake valve opening, only after it sits and collects for a while.

Looks pretty white/gray to me. Since it has been doing it even when new to some extent, I'd think a worn guide wouldn't be the cause...but not impossible. I was looking at some parts manuals and found there is a valve stem seal on the intake valve....maybe that was installed wrong or damaged during assembly?

[supertech]

The majority of those engines did that. The oil is fed through the valve guides when sitting. It's not a problem; it's a good sign that the guides are being lubricated. Drive it.
Mike

[homelink63]

I have a John Deere with the same engine. Does the same exact thing. I have always maintained it since I am in the engine business. Never noticed low oil or any other problem. Just normal operation I would say.
Jim

[clempot911]

I do see a bunch of people reporting the same thing. I’m surprised that an engine company would consider this normal and let that go to market – a cloud of smoke when you start it up doesn’t exactly inspire a feeling of quality or confidence. I’m even more surprised that this engine is ‘EPA’ certified or whatever they call it...they must not start testing until it's running

[clempot911]

Well I contacted Kohler about this and here is their response:

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Thank you for your inquiry. The white/gray smoke you see occasionally is normally the result of excess fuel "washing" down oil off of your cylinder bores. This can be caused by a slightly flooding carburetor ( To correct, the carburetor needle/seat will require cleaning) or by a sticking, misadjusted or overused choke, which will also cause excess fuel to be drawn into the engine. The other causes could be improper shutdown (always turn the engine off at 1/2 to 3/4 throttle) or a slight "cylinder downward engine mounting angle which allows the oil to sometimes seep into the cylinder and cause smoke on startup. A slight puff on these engines with vertically configured cylinders is considered normal as long as they do not exhibit excessive oil consumption.
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I responded that the tractor manual states to let the tractor idle for at least 30 sec. prior to shutting down or it may backfire (which it will) so doing a 1/2 to 3/4 throttle shutdown would have my neighbors ducking for cover, so I'm questioning if that's actually correct, but they haven't responded yet

[BO]

I have a 12.5 Command that does the same thing sometimes, not all the time and it hadn't always done it---but it is a 91 model-still uses absolutely no oil and oil stays clear.