Guys,

once again I need your expert assistance,

I have a Grasshopper front mount mower in the shop with a Kohler M18 engine, spec. # 24608.

customer replaced crank oil seal because of it leaking oil. New oil seal still leaked , brought it to me. also complained about lack of power.

I ran it in my yard a minute, did lack power, I saw oil vaporizing out around crankcase breather and oil filler cap, upon unscrewing oil fill cap , the pressure in the fill tube about blew the cap out of my hand, thats how much crankcase pressure there was.

I disassembled the breather assy. there is a small T-shaped rubber thing in there Kohler calls it a " Umbrella Valve" part #52-462-01. It is cracked in several places. also when I blew and sucked on the breather tube that hooks to the air cleaner, it did not act as a check valve, it left pressure pass both ways.

could the breather be all of my probem?? would a bad breather make that much pressure in the crankcase??

Does that explain the lack of power??

I'm more inclined to think bad head gasket, but I want to see what you all think first.

thanks,

Mark

I doubt that the cause of the excess pressure is caused by the breather assembly. I would be more inclined to look at a blown head gasket or worn rings. A leak down test would tell more about the head gasket and or rings. Regardless of this the breather needs to work properly, so you could always fix it first and see if it makes any difference, before moving on to any other issues.