Kohler CV23 smokes on startup..Normal?

[SmilinSam]

Got a Prestige that I replaced the blown up cv23 on with another cv23.

The new used cv23 is out of a Lowes Deere L130 and has about 300 hours on it. Starts and runs great, doesn't smoke while running and oil level stays the same on the stick.

However everytime you start it up after its been sitting level, it pumps out a big cloud of smoke then clears right up.

If you park the front of the tractor up on a pair of car ramps it doesn't smoke at start up. At least that's how its been so far.

Reading a few stories on these cv23's it seems almost as normal for this particular engine...whether brand new or used for a few hundred hours

http://www.lawnsite.com/showthread.php?t=330947

http://www.tractorbynet.com/forums/john-deere-lawn-garden/63606-john-deere-l130-smokes.html

Any opinions?

[Mike_H]

Could be an extra heavy shot of fuel...like an extremely effective choke. Is the smoke dark colored or white? Don't quote me on this, but I think dark smoke indicates a rich condition, while white or blue is oil burning off.

Found this...Has a nice troubleshooting diagram. Its geared toward automobiles, but Most of the same concepts apply.

LINK

[SmilinSam]

Its a nice bright white billowing cloud of smoke...

I am also using synthetic oil at the moment. Though in the reading I have done others have the same problem regardless off oil type.

[Mike_H]

If it happens only after start-up and sitting, you may be burning condensation out the the engine? Like when the as the engine cools from the last time its been run, you get condensation on the cylinder walls...and then when you fire it up, the condensation "burns" off in the form of steam. I'm guessing here. Typically bright white smoke is actually steam...

[SmilinSam]

Smells like burning oil though and hangs in the air unlike steam.

If it were condensation it would do that whether the front of the tractor was level or up in the air I would think.

Did you read the stories in the links above?

[Talntedmrgreen]

Sam, the CV20 in my Prestige does the exact same thing...on rare occassion, the CH25's I have had in Legacy's would also. It doesn't appear or smell rich to me, I believe it to be burnt oil.

Mine only does it on the first startup. If I've had the tractor running that day, and fire it up later, no smoke. My CV20 always requires choke to start when cooled to ambient temp, but will only smoke when started after sitting for a day or more. It's peculiar, but the engine has under 50hrs on it, and since I had become accustomed to it in the other machines, I just hammer down. Oil looks very good and doesn't budge.

[powerking_one]

Sam,

To me it may be oil "pooling" in the OHV/rocker boxes and oil is getting past the valve stem seals during the cool down cycle(s). This could be a crankcase breather issue also where during the cool down cycle, negative pressure in the engine/crankcase draws oil into the cylinders past the rings and valve stems. Without doing a parts/IPL lookup, I don't know if these Kohler's use valve stem seals or not; probably yes.

You might try draining out ~~ 1/4 quart of oil from the crankcase and see it that makes a difference.

Tom (PK)

[B112_son]

I had the CV23 in my L130 and it did the same thing. Sold it with 300 hours but used it for 5 years and it never showed signs of using any oil. I now have a prestige with CV23 and it does it as well my prestige has 600 hours on it and I just got it this spring. The only difference I have noticed so far is my L130 pretty much always had to be choked at start up. Even if the engine was warm. My smoke would only come on the initial start up however. My prestige only needs choke the first start of the day. Not sure what makes the difference between the two but that has been my experience.

[SmilinSam]

Nice to hear, as I can set my worries aside and count the transplant as a success.

I tend to agree with the idea of oil seeping by the valves. Like I said, when I park it with the nose up in the air on car ramps, it doesn't smoke.

Thanks all.

[CarlH]

Re PK: valve stem seals

Some Commands use valve stem seals but not all do. I have never torn down a CV but none of the CH's I have worked on had valve stem seals. YMMVsm01

[Smolenski7]

I know this is a thread that has not been posted to in over a month, but I have had the same problem with the CV23 in my Prestige. I just bought it used off of CL with 225 hours on it. After some work, I have it running pretty darn good.

My CV23 was doing the same thing at startup. Lots of white smoke. Most guys I chatted with chalked it up to just a characteristic of the engine. However, then I came across a guy who said that the rings never seated and the cylinders are now glazed and the rings didn't seal well. At shutdown some oil gets pulled past the rings if a cylinder stops on a suction stroke.

He suggested an oil change using break-in oil, then running the engine for about 25 hours really hard. I think what he meant was that the zinc in the oil should reglaze the cylinders which in turn would help the rings seat better.

I couldn't get my hands on any break in oil, however, I did try Valvoline VR1 Racing Oil; it has a high zinc content. I only have about 4+ hours on the engine since the oil change so it's a little early to come to any conclusions, however, it is clearly smoking much less.

I started off trying to run it at least 30 - 45 minutes every day, but I recently skipped a day just to let the oil sit. I started it today and it was fine. I'm starting to think that he was right and that the rings simply were not seated correctly and the zinc is helping them.

[dhoadley]

Good to know & thanx for sharing. I learn something new here nearly every day.

[Kenh]

From an automotive stand point a cloud of oil smoke on start up is loose valve guides or bad seals on the valve stems. Smoking while running is a ring issue.

Usually when the cylinder glazes over without seating the rings the only cure is to hone/break the glaze and install a new set of rings. You have to run an engine fairly hard to make the rings seat properly. The time frame to make this happen is actually pretty short. Maybe as little as 1 or 2 hours of run time. Many engines get started in the shop of the dealership and run outside for display in the morning and run back in at night. This is the WORST thing you can do to an engine. It never gets warm and the rings never get enough pressure to get properly seated.

This guy is promoting a "controversial" procedure to break in an engine. I was taught this way back in 1973 when I thought I wanted to be an auto mechanic. Nothing new by any means and every engine I've rebuilt used this procedure and I've never had an oil burner. http://www.mototuneusa.com/break_in_secrets.htm

Ken

[SmilinSam]

Been well over a month since my last post, multiple startups, and a dozen hours of run time, and with the tractor parked, front propped up on ramps, it does not smoke on startup. Is not losing oil either.

[joelk]

I have the same 23hp in my Prestige. I found that my smoke at startup occurs from the choke. If I try starting it without the choke, and slowly increase the choke until it fires, there is no smoke. I have not tried the ramps, but that is my experience. It also uses no oil.

[dentwizz]

I had one machine shop install stem seals on one that didn't have them and it helped some. Is this a vertical shaft design? If so they are prone to cold-piston ring seepage. However minor it may be, just because the bore doesn't get as much gravity/distance to help the oil go back. It will last longer as such but the cost of a minor amount of start up oil. If the engine is run long/hot enough to burn the plugs clean the pre-oiling is good for the longevity of the rings.