Small Engines (Lawn Mowers, etc.): Crankcase oil-gassey?, roto hoe tiller, crankcase oil

Question
I have a Roto-Hoe Tiller Model 910-3 with a 5 HP Tecumseh engine. It ran fine last year. I let it set for a season and went to check the oil dipstick. Oil had a gas smell on the stick, I drained crankcase and it ran out real thin, like black gasoline. What could it be? Should I refill it with 30 wt oil- and try it?
Thank you.

Answer
Likely the carb has been flooding, and the excess has made its way into your crankcase.  The older style tecumseh carbs, have a brass
float, that can develope a leak, and fill up with fuel, and not raise up high enough to cut off the fuel, or in some cases, if water
was present in the carb last fall, then froze during the winter,
and the float was crushed, either way, you should peek in the carb.
Give me your model numbers off of the engine, and I can give you the easiest way to do it.