Oil coming from breather plate

[JimSraj 499]

There is a thin coating of oil on the front of the k301 that I rebuilt summer before last. It looks like it’s coming from the breather plate, best I can tell. It had been leaking there after the rebuild and I redid the gaskets and replaced everything in proper order. The leak stopped!  Tractor’s been sitting for a few months while I pulled the trans to replace bearings and seals. Now that the trans is back together and in I’m running it around to make sure all is well and noticed the thin film of oil on the front of the engine. 
Any ideas as to the cause?

[squonk 43,208]

It's not uncommon for a little oil mist to come out of the breather hole. These crankcases have to breath some or the seals will blow out. How bout a pic? An engine not breathing just cost us 8 grand to fix on my son's car so if it isn't excessive I wouldn't worry about it. By rebuilt was it rebored? New guides? 

[953 nut 58,998]

A leak-down test will let you know where to look if any problems are cropping up.

 

[JimSraj 499]

The cylinder was bored 10 over and the crank to 10 under.  Head was milled too. I did not replace the valve guides. l wiped off most of the oil that was on it so I’ll will get some pictures next time I run it. 
A leak down test sounds like a good idea. Never done one and don’t have a tester though. 

[kpinnc 14,143]

As has been said, these old Kohlers "burp" a little, and that is normal.

 

One thing: you said everything was installed correctly. Are you certain the breather valve is correctly installed? Those little plates allow for air to move one way only, but only if stacked up per the manual. 

 

And again, a little "wetting" around the valves is not uncommon. Oil naturally wicks out of even sealed openings a little. So long as it isn't spitting from there I would say it's expected.

Edited March 15, 2023 by kpinnc

[JimSraj 499]

I followed the manual when installing the breather assembly. Maybe I’m being too fussy about the oil on the front of the engine. As I said, I’ll get some pictures posted soon. 

[OutdoorEnvy 1,761]

You might double check the oil level is correct and no gas is in it.  If you have gas leaking into the engine it will fill the crankcase over time and it will leak more like that if it's overfull.  If there is gas in it you likely have two issues, one would be leaking from the carb by either a stuck float or bad needle and seat, second would be leaking from the fuel pump.  

 

Also if your dispstick is the screw in one you check the oil level with it unscrewed against the lower side of the flange.   

Edited March 15, 2023 by OutdoorEnvy

[JimSraj 499]

Oil level is good and I don’t smell any gas odors. Viscosity seems fine also. 
Here are a couple of pictures taken this morning after it ran for about 20 minutes. 
I was keeping an eye on the breather plate as it was running and could not see any oil or even mist coming from anywhere but there was enough oil on the block and front of the oil pan below the breather to catch a coating of dust. 

 

[Handy Don 13,581]

36 minutes ago, JimSraj said:

oil pan below the breather to catch a coating of dust.

Only thing that comes to mind is if the mesh in the breather is in place and intact.

Over a few hours usage, I do get an oil residue on the front of my 181. Like you, I noticed it because it collects dust .

 

BTW, is the throttle cable housing going to interfere with the governor arm where they cross or is it just the camera angle?

[Rob J. 1,942]

My 10hp does the same thing but I haven’t changed the gaskets for the plate either. It’s a real thin film of oil that comes out like you state. It looks worse than it is. 

[squonk 43,208]

I wouldn't worry about it. The mesh in the breather will collect oil droplets but nothing will stop any vaporized oil.

[kpinnc 14,143]

Looks completely normal to me.

[JimSraj 499]

Well thanks to all of you. I guess I’m being a little too particular about it. Good to know that others have the same experience with their tractors. 

Don, it’s the camera angle. I fashioned the  bracket that holds both cables bc I didn’t like their positions. There is no interference with the governor arm. 

[wallfish 17,778]

Normal. The case pressure needs to be released through that valve. The mesh will catch the majority and it drips back.

Imagine the oil dipper splashing and bashing into the oil in the pan and doing it often and very fast. (Every revolution of the crank shaft) Some of those particles are going to get pretty small, vaporize and escape with the case pressure air. Newer engines typically send that air via a hose into the air filter assembly to re-burn