Mine did that...neighbors didn't seem to like it much. It was worn/sticking rings in my case. The problem was worse during cool months and during the first 15 minutes of operation. It became progressively worse over time. In my case, I was burning a 1/2 quart of oil per hour or so. I finally rebuilt the engine.
Does one or both of your plugs look fouled?
I do a compression test and check the plugs and breather.Here is a similar issue, but no solution:
Hi, I have a Kawasaki fd611v that puchs oil into the carb from the breather hose. It does not happen all the time. Just when you stop. The engine runs fine otherwise. I have checked the reed valves and the crankcase vacumm. The vacumm is 3 inches of water. This is in a john deere gx345 so...www.lawnmowerforum.com
Here's one that points to the breather valve and/or the dipstick. I swapped dip sticks with my X300 (it is shorter, but the otherwise fits) and the problem stayed with the X534. So, I think it is the breather valve. They also have an upgraded cover and removed the filter, so that might have something to do with it. It's a partial teardown to access it, so I haven't done it yet.
Have a 20 hp kaw horz shaft engine, compression test is 170 lb on each cyl. But its got so much pressure in the crankcase that it blows the dip stick out, and if you remove the filler cap, oil blows all over your hand. It also blows oil into the air filter, causing the engine to smoke. I can see...www.mytractorforum.com
Here is one that says it was rings:
I am not sure I agree with the testing. I did a leakdown test on my X300 which runs fine normally (to make sure I knew how to do it and also to check its health). I forgot to remove oil dip stick before pressurized. It was fine for several seconds, and then it wasn't. Oil gushed out of the breather and made a huge mess. On my X534, I had both plugs out and heard weird gurgling sounds as I turned the crankshaft by hand. I looked at the output of the breather tube and there was oil there. So, the breather is supposed to remove excess air from the crankcase to prevent the crankcase from getting pressurized. The crankcase volume changes as the pistons go in and out. The breather valve is supposed to let air out (when the piston goes down into the crankcase, it reduces the volume, normally this would increase the pressure). When the piston goes back up, the breather valve is supposed to close and prevent any air from coming in. If it is working correctly, this will create a partial vacuum, since a smaller amount of air is filling a larger space. If the valve is letting air go both ways, this causes a lot of air to go in and out via the breather. That will overwhelm the chamber that is supposed to remove the oil from it.Go to page 20 in this link to a Kohler engine service manual. It has a good set of instructions on vacuum/pressure testing and lists causes and conclusions of pressure in a crankcase. http://www.kohlerengines.com/onlinecatalog/pdf/24_690_06_EN.pdf Page 21 gives good info on compression tests and...www.lawnsite.com
As an FYI - the FD611V doesn't have a filter in the breather cavity. There are baffles that are cast in as part of the block but no filter.I suspect that is what is going on with my X534. It probably still has the filter in the cavity. Newer models don't have that and have a thicker cover (to help prevent leaks). The service manual also says to "check for slugs blocking the drain hole", but I suspect they meant sludge. After I take it apart (and put it back together) I will have a better idea of what is causing the problem.