Small Engines (Lawn Mowers, etc.): john deere riding mower engine, briggs and stratton, hp model

Question
My John Deere with a Briggs and Stratton 15.5 hp Model 28N707 type 1135-E1 Code 981215ZE, I ran out of gas, had to drive the car to the station and fill up my gas can, then returned home and filled up my mower, sat down and the motor turned 1/2 to one turn. I removed the air filter and found gas all over and it filled up the carb. I pinched the gas line from the tank. I pulled the plug and gas ran out. I turned the motor over and blew all of the gas out, then installed the plug and it fired and ran for 15 to 20 seconds, and the same thing happened but this time it look like oil in the carb, my oil level it to high and has gas in it, I have drained the oil and it is very runny. there is a electronic part on the bottom of the carb.
Any helpful ideas would be great.

Thanks

Curt


Answer
The inlet needle valve is leaking.  The electonic part on the bottom of the carb is an anti-afterfire solenoid to prevent the engine from backfiring when you shut if off.

There may be some dirt/debris in the carburetor causing the inlet need not to seal.  Usually this happens when you run out of gas or the inlet needle/seat get old.

I would recommend removing, dis-assembling the carb and cleaning with compressed air from an air compressor.  While there, replace the inlet needle and seat as they are old.

Drain the oil and remove the spark plug.  With the oil drained and spark plug removed, turn the engine over to flush any oil/gas that may have entered the cylinder.  Refill with oil, turn the engine over to lubricate the parts before re-installing the spark plug.

Inlet needle part number:

for Walbro carb 231855
for Nikki carb 696136


Carburetor overhaul link:

http://faqs.custhelp.com/cgi-bin/faqs.cfg/php/enduser/std_adp.php?p_faqid=3440&p...

Let me know if this helps.
Eric