MERCEDES — Morgan Jones gritted her teeth as she ground the pedals forward.

“C’mon! Whooo!” shouted onlookers as Morgan, 11, pulled 225 pounds of metal plates toward the finish line yesterday at the Kids Pedal Tractor Pull.

The event at the Rio Grande Valley Livestock Show invited children ages 4 to 12 to pull the weight sled 25 feet. If they made the first round, they had the chance to compete with more weight through a process of elimination.

The course was marked according to distance.

Danny Kollaja, the host, addressed the crowd.

“When they get to 15 feet, 20 and 25, get louder,” he told onlookers. “You applaud, you cheer. They will go faster.”

Kollaja laughed and joked with kids and adults alike, and there was something familiar in his humor. That’s because just an hour earlier, he’d been Lanky the Clown with the red nose and wild hair.

Later in the day he’d be Marshall Slim, the 10-foot tall Cowboy walking around in stilts. He would also work with the Pig Scramble that evening.

As Morgan and her competitor, Robert Vallejo Jr., 9, grimaced on their way to the finish line, Kollaja encouraged each child with his affable humor.

Finally, at the end of the race, Morgan said she enjoyed the experience.

“It was fun,” she said. “I have never done it before so it was a great new experience.”

She thought for a moment and then added, “It was hard.”

Her father Ron was equally pleased.

“We enjoy doing stuff like this,” he said.

When he learned Kollaja was also the clown who’d been to Afghanistan to help injured children, he was even more impressed.

“That’s awesome,” he said. “As a veteran, to take time out to help these kids and give back is great.”

Meanwhile, Robert prepared to try his hand at a second round by pulling an additional 50 pounds.

“If you do well,” Kollaja told him, “you will get to drive the vacuum cleaner.”

Robert wasn’t sure how he felt about that, but he climbed onto the tractor just the same, pedaling hard to the finish line.

“Go, Go, Go, Robert!” shouted his family as his body lurched forward in fits of strenuous pedaling. Alas, he almost made it, but not quite. Robert would not get to ride the family vacuum cleaner, at least not for awhile.