Hi I tryed and asked about tuning rpm by ear,I do it with guitars and basses,all the time. well got the tach made by moose utility div, I tuned the the vanguard to 3600 rpm,but with load rpms droped to 2400, kept playing with it, I found a sweat spot around 3000 rpms where the TORQ PEAKS with no load,sounded good and with load rpms droped only by 50 (with load 2950) so I checked before starting that both cly are working. now I think something is wrong with miss info from briggs,this engine is rated @ 3600 @18hp.I think I have a 16 or 14 hp rated at 3000 @ best! is due to EPA? or is something on my engine srewed up?