Time for another new tire.
I had a sidewall repaired on a car one time. It made it 2 or 3 miles down the interstate and disentegrated!!!!! It almost killed me and about 10 other people!! If I got a slice in the sidewall of my 4 wheeler tire, I would trash it and get a new one, unless you fear nothing. The way I see it, I will spend $120.00 or so, to stay alive, any day!! Just my opinion!
fatsam,If I knew you, I would be glad to give it to you. I was using my opinion about this. I used to work as a tire repairman/salesman, and I know that the side wall, on anything, (car, 4 wheeler, lawnmower) is under more stress than any other location. I know you wont be doing 80 mph in a mud pit, but I belive you are better safem then sorry. But dirty4man has a good short term fix, tube the tire!