mattd860 162 #1 Posted September 19, 2011 I ran the 20hp Onan on my 520H without the air filter and saw oil spraying out of the breather. I also noticed the Low Oil Pressure light was blinking. In addition the tractor puffs blue smoke out of the exhaust when I increase rpms. I haven't done a compression test but I'm fairly certain the rings are toast due to the blue exhaust smoke. However, what would cause oil to spray out of the breather? It's not really a spray - it's more of a 'mist'. The tractor runs fine otherwise and has a lot of power, idles smooth, and rev's up without choking. If I didn't see smoke out of the exhaust or the oil breather, or the blinking pressure light, I wouldn't even know there was a problem. Share this post Link to post Share on other sites
woodchuckfarmer 333 #2 Posted September 19, 2011 Sounds like my 520. It turned out to be the intake valve seats were out of the block. Share this post Link to post Share on other sites
condo630 6 #3 Posted September 19, 2011 Worn piston rings can cause that. Combustion gases get pat the worn rings into the crank case and blow oil mist out the breather. How many hours are on it? I don't know what could cause the oil pressure light to flicker, I'm not familiar with pressurized oil systems. Share this post Link to post Share on other sites
Olratlr 25 #4 Posted September 19, 2011 I just recently put Rings in a K482-5 in a D 180 it was blowing oil out the filler tube and at tear down found out the rings had a good 1/4 gap in them not supposed to have but thirty thousand.New Rings no blow by. :thumbs2: Share this post Link to post Share on other sites
