I was recently got a craftsman 740..or 720 riding lawnmower its old..in very nice condition..and I never heard anything soo quiet before..It prob around maybe 1990 or even earlier..3 speeds with .a pullrope to start...Im wondering any info..on what I should put in it..as oil? and or info on anything else....I never heard anything soo quiet even the brand new ones!! ..unless its a electric one.. help anyone???