Mud flew, crowds cheered and checkered flags waved for the 21st year of lawn mower races at the Amboy Territorial Days Celebration Sunday afternoon.The day starts with time trials to determine the starting order come time for the real races.David Newton said his wife, Kristi Thorson, was kind enough to share her mower after his encountered belt trouble.“She was nice enough to let me ride it,” he said, adding he hoped not to flip one over that day. Again.“Personally, I want to start on the inside, because that’s easier to hold your line when you come into that corner, and pushes them out,” he said. “Pushes the other riders out into the duff, slows them down, and you keep your speed.”He’s been racing lawn mowers for about 12 years, and it’s grown into a family affair.Along with his wife, his dad races as well, he said, as does her father, Kyle Thorson, who spread his habit to many others on the track that day.“He got me addicted to it, and after that it was over with,” Marty Ebert said from his impromptu mower pit at the edge of the arena. “First time I rode one, I had to build it.”To make his mower race-worthy, he fiddled with the pulleys that turn the wheels, removed the governor and tweaked the engine.Riders get pretty creative with finding ways to squeeze more power from 8-horsepower lawn mower engines, he said, some build souped-up, alcohol-burning speedsters.“Keeping up with them with a stock motor’s fun,” he said, with some pride.Generally, the requirements are pretty loose, he said: maintain the general riding mower appearance, engine and frame. (The blades are removed.)“Being a fabrication welder helps,” he said, adding he built his with scrap metal salvaged from work.The races followed a day of precision falling, bucking logs at speed and other feats of chain saw mastery Saturday.Sam Arola, chief of Fire District 10 and the one corralling all the racers, has been volunteering with the lawn mower races since they stared in 1996.