Valparaiso led 14-10 in the second quarter before Carkhuff gave the Wildcats (4-7, 2-6 Pioneer Football League) the lead for good at 16-14 on a 5-yard touchdown pass to Lanny Funsten with 51 seconds to go in the first half.
Carkhuff, who threw three interceptions, added a 1-yard touchdown run and Chase Culbertson scored on a 4-yard run in the third quarter as the lead grew to 30-14.
Eric Hoffman had a big day for the Crusaders (1-10, 1-7), passing for 364 yards and two touchdowns, but he was sacked five times. Hoffman threw a 10-yard touchdown pass to Cole Anderson with 1:55 remaining for the final margin. Davidson covered the ensuing onside kick and ran out the clock to preserve the win.