Eton and Mud Pits

My son has an 05 Viper 70 and likes to go in the water and mud with me. He doesn't go in anything deeper than half a foot at the max. It seems that after a little while getting wet his Eton likes to either die when he hits the gas or sputter so bad that it barely moves. We are fairly new to quads and am still learning myself. It doesn't appear any water is getting in the air box but was wondering if there is anything I can do or cover to prevent it from riding so crappy once wet?

Thanks,
Chuck