Kohler Command Pro 25 blowing smoke at start up

[dean7777]

I have a Snapper zero turn with a Kohler command pro 25 model CV730. At start up it blows quite a bit of blue smoke, after a minute or two it stops. The crankcase is not overfilled with oil, probably slightly under filled. Any suggestions would be greatly appreciated. Also would anyone recommend oil treatments / additives? Thanks

 

[brokenot]

If this just started happening, it may be an early sign that one of the head gaskets is starting to fail. Head gasket issues were very common on these engines a few years ago....later models not so much I think.

If memory serves, one of the suspected causes of the gasket failures, was the proximity of one or more of the head bolts to the exhaust port. Over time and after repeated heating/cooling cycles, the bolts lost enough of their tension to cause the gasket to start deteriorating. Replacing the gaskets on these isn't a hard job at all, but I would do some Googling to see if the engine you have is one of the affected ones before proceeding. I'd also check and see if bolt replacement is recommended when the gaskets are changed out.

 

[Redneck in training]

It might be also something simple as dirty air filter.

 

[Leo Rabon]

It might be also something simple as dirty air filter.

Ditto. Redneck. The Kohler engines "don't like a dirty air filter". I had the same problem with a 20 HP Command. A new air filter cleared the smoke up. Keep the air filter clean.

Leo

 

[dean7777]

Thanks for the suggestions. I replaced both primary and secondary air filters. It still blows blue smoke at start up.

 

[jaotguy]

another cause can be the valve guides are getting worn .....

 

[dean7777]

Thanks jaotguy

After doing some research, worn valve guides are the probable cause of the blue smoke at start up.

 

[Stimw]

How many hours are on the engine?
Some of the Kohler engines have a valve stem seal on the intake valve just like car engines. The seal might have failed.

 

[jaotguy]

and the usual reason for the seal to fail is over sized /worn guides ... allowing the valve stem to wear the seal .....

some shops can knurl the guide to control the oil ( old school stuff )

 

[john_bud]

Thanks jaotguy

After doing some research, worn valve guides are the probable cause of the blue smoke at start up.

Let it warm up, throttle it up all the way. Then QUICKLY go to idle. If it blows blue smoke then, it's the guides/valves. (vacuum sucking oil in). If it blows blue smoke when you throttle up ... rings.

Just when initially cold, it could be the head gasket. (mine was). Or it could be the flapper valve deal. I forget what it's called, but it controls engine blowby.

Have you done a compression test yet?