I've been running karts for a while and now i want to build a mower.  I bought a bunch of blowed up vertical shaft engines.   I plan to run single cyl modifed.  my question is how do i tell a model 28 from a 19 when there in a box with no shrouds. and wich one is better to use.  also in my travels looking for parts engins which ones should i look for?