Kasperbauer scored 11 during a 19-0 run that gave the Coyotes (10-10, 2-4 Summit) the lead for good, turning a five-point deficit at 12:58 into a 66-52 lead less than five minutes later.
The Leathernecks (7-10, 0-6) traded baskets before answering with eight straight points to get within 68-62 on J.C. Fuller's 3-pointer with 6:27 left. They would get no closer and went scoreless over the final 2:13.
Fuller led Western Illinois with 16 points. Garret Covington added 13 points and Tate Stensgaard scored 10. The Leathernecks had a five-point lead at halftime and stretched it to 47-37 with 17:23 to go.