John Deere 420 Price, Specs, Review, Horsepower, Serial Numbers, Attachments, Weight, Engine Oil Capacity, & Pictures John Deere 420 Specs, Price, Review: John Deere 420 Garden Tractor is equipped with an Onan B48G gasoline 2-cylinder air-cooled opposed-twin, 781cc engine, which delivers 20 hp (14.9 kW) power. John Deere 420 Garden Tractor featured with 20HP Onan 781cc … [Read more...] about John Deere 420 Garden Tractor Price, Specs, Review & Attachments