Small Engines (Lawn Mowers, etc.): 8hp briggs will not start, briggs stratton engine, briggs stratton

Question
My neighbor gave me his supertomahawk chipper shredder. 8hp briggs. model 195437 . It will not fire up, I used starting fluid and it trys but will not kick over. I replaced the ignition modul and cleaned the carb and still it cant seem to crank over. I do not see an external fuel pump. the carb is definately getting gas. I took the head off and the valves are seating properly and look clean. Is the fuel pump diaphram under the breather element. What should I try next?

Answer
Dear Tom,

I'd need the serial no. of the [Briggs & Stratton] engine, to answer you about the pump diaphram ...
As per the hard starting, have you checked out the condition of the Spark Plug? I recommend trying to test to be certain there's electrical power to the plug.   
Has the gas been switched for fresh gas? Gas that is over three months old could be a part of the problem. Are the fuel lines working properly?   
Is there a fuel filter?

Get back to me.