Small Engines (Lawn Mowers, etc.): 12 HP B&S mower, blade adjustment, exhaust muffler

Question
Eric,

You've saved me so far (9/13/10 flywheel issues) so I'm back to you again...12HP B&S Model# 282707 Type 012201 got her running, cut a bit of grass and needed to make blade adjustment and went to start again and gas starting streaming out of the exhaust muffler until gas tank was empty. I drained the oil which at this point smelled of gas...but then everything did actually.  I had rebuilt carb awhile back but mower has been out of commission for a long period of time.  Could it be as simple as the carb float valve not seating? Would excessive carbon build up in the compression chamber cause the valve not to seat and gas pour out from exhaust?  I definitely need the benefit of your expertise, in other words - Help, please!  Thank you and again, I appreciate your advice & help.  

Answer
Most likely it is the inlet needle.  The seat is also replacable but you have to pull the old seat out and press in the new one.

To save some money, you can replace the needle.  If you want to replace the seat as well I'd take the carb to your local shop and have them replace it as they should have special tools to replace it.

If you want to replace the seat yourself you can tap the seat with a 1/4 inch 20 threads per inch (national course threads) and use a small pipe or socket that fits over the seat.  Once tapped, use a bolt and nut fed through the socket or pipe.  Thread the bolt and then turn the nut to pull out the seat.  Press a new seat using the old seat as a  tool and vice.  Easy done than said.

An alternative to both is just to install an inline fuel shut-off valve.  Just turn the valve off and let the mower die (run out of gas)when you are done mower.  Cheapest repair and guarantted not to leak gas in your oil.  I use a lot of fuel shut-off valves and have only had a few leak after several years of use.

Let me know if this helps.
Eric