Repairs CRAFTSMAN LT2000 - BLUE SMOKE & WON'T STAY RUNNING

[BRZFAN]

I'm looking for help to diagnose the 'subject' problem I've recently experienced with my '03? Craftsman LT2000 lawn tractor.
The last time I used it, it ran fine. When I started it this week, there was alot of heavy 'blue' smoke form the exhaust and it will stay running for only 15-20 seconds. It will restart, but not stay running.
I assumed from the smoke and it's inability to stay running that I have 'burnt' or 'froze' a piston ring and it would not maintain enough compression to keep running??
I checked the oil level, it's ok, but appears to be thin, like it has gas in it? Before I 'junk' the mower, or replace the engine, I would like to know if this sounds like a problem I can fix?
SPEC'S:
'03 CRAFTSMAN LT2000
MODEL#917.273130
ENGINE- KOHLER 17 HP OHV (490 cc)
OEM#177745
FAMILY#3KHXS.4902GB (for wahtever its worth?)
I appreciate any help that anyone may be able to provide.

BRZFAN

 

[EngineMan]

Drain the old oil out replace with new and then take out the spark plug and clean it, turn it over a few times before putting the plug back in, refit plug and start it if you can, it may smoke for a few minute's but then go away, if after that it run's ok, you need to clean the carb or if it's fitted with a fuel solenoid check it to see if it's working, if not replace it, it may well be worth you fitting a fuel tap in line also if you have fuel in the oil, let us know what you do and how you get on.