First, we need to convert the weight of the average-sized pumpkin from grams to kilograms. Since 1 kilogram equals 1000 grams, we can perform the following calculation:
\[ \text{Average-sized pumpkin weight in kg} = \frac{5000 \text{ grams}}{1000 \text{ grams/kg}} = 5 \text{ kg} \]
Now, we can find out how much more the world-record pumpkin weighs compared to the average-sized pumpkin by subtracting the weight of the average pumpkin from that of the world-record pumpkin:
\[ \text{Weight difference} = \text{World-record pumpkin weight} - \text{Average-sized pumpkin weight} \]
Substituting the weights:
\[ \text{Weight difference} = 913 \text{ kg} - 5 \text{ kg} = 908 \text{ kg} \]
Thus, the world-record pumpkin weighs 908 kilograms more than an average-sized pumpkin.