Kohler magnum 12 crank case pressure

[moe1965 753]

I finally got the magnum 12 running today I'm not familiar with this engine and only worked on the older Kohler engines.  It started right up after I figured out the electrical issues and this tractor hasn't ran in about 5 years .   I let it run for about a half hr and noticed while running I took out the dip stick and there was quite a bit of air pushing out of the dip stick tube.   Is this normal.  It puffs some smoke out at throttle up but nothing that makes me think there is a major valve or ring issue.     Any thoughts???

[Howie 899]

It is common for one of these to blow oil out the dipstick tube if you remove the dipstick.

There is a lot of oil flying around in there when they are running. Have changed oil and

gotten distracted and left dipstick out, started engine and gotten an oil bath.

[gwest_ca-(File Mod) 11,445]

That is normal. Think about it. The top of the piston is sucking on intake and blowing when the piston is coming up for exhaust. The bottom of the piston is doing the opposite at the same time. About 60 cubic inches of air on each stroke - 30 on top and 30 below the piston.

There is a check valve in the breather over the valve springs. When the piston goes down it pushes the air out the breather. When the piston goes up the check valve in the breather closes and creates a vacuum in the crankcase and this vacuum should be constant as the engine runs. Of course the dip stick must be installed to maintain the vacuum. Just like the pcv valve in an auto.

 

Would not hurt to dismantle the breather assembly to clean it and the filter and check valve adjustment at the same time.

The only difference between a K-Series and a M-Series is the ignition.

 

[moe1965 753]

Thanks for such a quick response I  checked the breather which I could feal a little blow by but nothing like from the dipstick tube.   I will check the valve adjustment next.  I can't believe how quiet the engine sounds 

Edited September 18, 2023 by moe1965