Small Engines (Lawn Mowers, etc.): Pulsajet carb, compression issue, valve job

Question
I have a 5hp Briggs on a generator.  I've asked you several questions concerning this already.  I throughly rebuilt the carb(carb cleaner, wire and compressed air) and it runs much better, but still rough at idle.   No matter what position the jet is in you cannot hear a difference.  This is a Pulsa-jet "fixed-jet" does that mean you don't adjust the jet?  The book says 11/2 turns out and adjust from there.  When I cleaned the carb I noticed the jet was not pointed, but very blunt!  Straight and clean, but blunt?  Any ideas?

Thanks,
Bob

Answer
The shape of the needle has more to do with the shape of the seat and not all are pointed.  However, this mixture adjustment does not affect the mixture at idle...that is preset.  As long as the carb is clean, the idle mixture should be properly calibrated.  Other issues related to poor running, especially at idle, are either an air leak between the carb and the engine or a compression issue.  If you spray WD-40 or something similar around the area of the intake tube connection points and hear the engine RPM change as a result, there is a leak.  If not, remove the spark plug lead from the plug and crank the engine over.  Listen for a whisping sound from the exhaust.  This indicates a leaking valve (burnt, incorrect tappet clearance).  This would require a valve job to correct.  Let me know what you find.