Small Engines (Lawn Mowers, etc.): Bolens riding tractor rpm, spring tension, needle jet

Question
I bought a Bolens 17hp Briggs 42in. cut mower 2yrs old.  It runs and starts fine but it won't come up on RPM.  I checked linkage, air cleaner, fuel filter, and took bottom of the carb. off everything seems fine.  The mower seems to be going way too slow.  When I engage the blades and I am in 8th gear I could walk faster than it goes.  My dads small snapper would smoke it.
Thanks Brian  

Answer
Hi Brian,

Check the throttle plate in the carb to be sure that it is opening up all the way.  Next, adjust the high speed needle jet on the carb.  Then try adjusting the governer spring tension or linkage.  

Let me know how you make out.
Michael