Kohler 17.5hp smoking

[Scooby]

I have a Scotts (JD) riding mower. It has a 17.5hp Kohler motor. It currently has 33 hours. At 5 hours I changed oil and filter with John Deere oil. At 25 hours I chaged to Mobil 1 10W-40 (grade called for) and WIX filter. I have noticed at idle that motor blows blue smoke. This did not occur before the Mobil 1 change.

Any ideas why this is?

Thanks

 

[MolaKule]

Mobil 1 10W40?

Check oil level again. Is this a horizontal or vertical cylinder?

 

[Scooby]

Sorry, meant 10w30.

Oil level is ok. Had not had to add any since change.

I dont know about engine type. I only know it is an overhead valve.

 

[Scooby]

Bump

Any more opinions?

 

[Bror Jace]

Scooby, It might be burning more oil because Mobil 1 is formulated to be on the thin side of a 30 weight at temperature.

Do you know for sure that it is actually consuming more? It may be that the Mobil 1 merely smokes a little more as it resists burning more than typical mineral-based oil stocks.

--- Bror Jace

 

[Scooby]

Does not seem to be consuming any or much, I havent added any in 7-8 hours since change.

 

[Bror Jace]

I've noticed that when I switched from conventional oils to Mobil 1 years ago, the smell I got in my car after an oil change (oil dripped onto the exhaust) was more intense and lasted longer with the synthetic.

I attribute this to the synthetic's resistance to burning off compared to mineral oils. The same explanation may explain the more noticeable color you see coming out of the engine. If the oil getting into the cylinders combusted more completely, it's color would probably not be the visible blue you see. I'm pretty sure the blue comes from oil particles which has atomized but hasn't really combusted.

Mobil 1 (Group IV synthetic) will flash off and combust at higher temperatures than mineral oils. It is likely that the combustion chamber conditions are insufficient to burn this stuff cleanly.

Since you are saying that consumption seems about the same with both oils, that's the best theory I can come up with.

All oils consume at least a tiny amount of oil and I wouldn't worry too much about it. If consumption increases and/or spark plug fouling becomes a problem, consider trying to get a replacement motor. Just save all pertinent documentation, etc ...

--- Bror Jace