Noticed yesterday that my mileage range has dropped considerably on my XR4. I made about a total run of about 15 miles yesterday and ran out one of my half tanks in just that run alone. Are my carbs out of adjustment causing it to use more fuel now? I was thinking that at about 40 mph steady speed, I was getting about 25-30 miles out of one tank. I know most people are running newer engines, but I really don't have the funds to make the purchase and it is still running. Thanks.