Small Engines (Lawn Mowers, etc.): Gas in the oil, viscosity of water, horizontal design

Question
I have a B&S motor model 287707, type 1224-E1.  Its a single cylinder, horizontal design.  Enough gas is leaking into the crankcase to keep it from turning over.  Removed and cleaned out the carb, orifice openings for the solenoid needle valve and float valve looked clean and unobstructed.  Any ideas on how else gas could be leaking into the crankcase?  The oil is so diluted its about the viscosity of water. functions free and easy, float

Answer
 Hello Bruce:

 Im Unsure of the Model Engine we are Speaking of, However the Carburator Float Needle Isnt Stopping the Flow of Gas to the Carburator. The Seat in the Carburator May be Pitted and Allowing this to Happen. Change the Oil. Run the Engine for 2 Minutes and Change the Oil Again. Install a Shut Off Valve in the Line from the Tank to the Carburator and Shut Off the Flow of Gas to the Carburator whenever the Mower isnt in Use. Send me the Model Number Off of the Engine and I may be Able to Better Assist you. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John