I really didn't hear any unusual noises, but the video was short and definitly not running
at full power. 
 
If the carb drain screw is loosened while running and fuel (a "decent" amount)
comes out, the fuel pump should be fine.
 
****Try spraying some carb cleaner down the carb throat and see if it revs up..
 
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Thanks Scott . . but I am surprised you can't hear the knock . . it is very loud and the engine jerks each time the noise is made.   Maybe I will try the long screwdriver to the ear bit and see if I can find the area that the noise is coming from . . . .

If the rod to crank gap(if worn out), you can sometimes "feel" it rocking the crankshaft back and forth
by the flywheel.  Get the piston about halfways up.  (Valve location doesn't matter)
 
 
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Thanks Scott for your help.  It turned out to be the ignition trigger that was way out of adjustment . .that was a miss not a rod knock!!   Happy!!

Yea, GREAT deal!!!
 
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