Small Engines (Lawn Mowers, etc.): Murray 6.5hp Quantum Mower Surging, briggs and stratton, wd 40

Question
Mr. Jones,
 I have a friends mower who wanted a tune-up.  I replaced the plug J19LM and found no air filter which we'll install.  I put fresh gas in it and it started right up and then the idle began to surge.  If I remove the carb to soak it, 1st - would sea foam or Gunk work? 2nd - do I disassemble the carb before soaking, 3d - is there a carb kit available for the 6.5hp Briggs and Stratton that I should use or is it easier to replace the carb if needed?  
 Am I tracking correct on what to do??
Thanks a bunch in advance!
Dan

Answer
Briggs does sell a carburetor kit.  You need the model and type number to order the kit or parts.  You can visit the Briggs web site and find the part number(s).  Since the mower runs, you should be able to remove, dis-assemble and clean the carb with spray carburetor cleaner and compressed air from an air compressor.
I would also recommend replaceing the air cleaner cover gasket if the mower has a primer bulb.  If you send me the model and type I can look up the parts for you.

The most challenging part to replace inside the carb is the inlet needle seat.  Use a dental pick to remove the old seat.  Once the old seat is removed, install the new seat "groove down".  Use a flat punch or old point plunger to install the new seat.  A little WD-40 aids seat installation.  Once installed replace the needle, float and float pin.  Turn the carb upside down and make sure the float is sitting approximately level or horizontal with the carb body.  This tells you the inlet needle seat is fully installed.

It's a pretty easy, straight forward job.
Let me know if this helps.
Eric