Small Engines (Lawn Mowers, etc.): 16HP BRIGGS GOVERNOR?, hp briggs, homelite generator

Question
I HAVE A HOMELITE GENERATOR MODEL 180A75-1 THAT USES A 16 HP BRIGGS ENGINE MODEL 326431 TYPE  0255-01   CODE  7707211   STARTS UP AND RUNS BUT  WILL RUN AT HIGH RPM THEN LOW RPM RAPIDLY BACK AND FORTH.  IS THIS A GOVERNOR PROBLEM?  BROKEN SPRING?  WHERE CAN I FIND INFO OR PICTURES ON THIS OLD ENGINE?    
 ANY HELP WOULD WOULD BE GREATLY APPRECIATED  THX CASEY

Answer
You can view an illustrated parts list diagram on the Briggs web site.

As for the surging, most likely the problem is the carburetor.  You carb can be difficult to repair...there are some tricks to getting it right.

Do you have an air compressor, single cylinder tachometer and any experience with carburetor rebuilding?
Have you tried turning the bottom jet in or out just a little to see if the surging will stop?
Let me know.
Eric