Small Engines (Lawn Mowers, etc.): john deere sabre mower, crankcase pressure, crankcase breather

Question
I have a John Deere Sabre riding mower.  Even with a new battery it turns over slow and inconsistent.  I can get it to start when I spray starting fluid in it, however, when it burns off the starting fluid it dies.  It blows alot of smoke and it is also blowing up the carburetor, OIL.  The only way I could get it to start was when I took the filter completely off, that's when I noticed it blew lots of oil out.  What does this mean?  Is it shot?  Or is it worth taking to somebody to look at?

Answer
Maybe not shot.

Drain the oil and refill with fresh oil. Check the plugs for oil fowling.

Remove the engine breather and be sure it is not full of oil. If it is replace it and the gasket.

If you are getting smoke and oil is in the carb you may just have positive crankcase pressure, you don't want this.  This pumps the oil out of the crankcaase. If the breather is ok you have an air leak in the crankcase.  Try the oil pan gasket, the o ring where the dip stick tube goes into the block and the seal on the dip stick. All have to be good.  Check top crankcase seal, under the flywheel. If the crankcase if full to the top with oil and gas you have a float pin not seating in the carb.  While the crankcase breather is out check valve clearance.  Those specs are on the engine mfg web site.

You say you have a good battery.  Did you check the voltage?  It should be at least 12.6V when fully charged. I think you have an engine problem not a electrical problem.

Try these first, if you do not find the problem we will have to remove the engine and tear it down for inspection.