Delon has 37 tickets and uses 4 tickets for the carousel. To find out how many tickets he has left for the roller coaster, we subtract the tickets he used for the carousel from his total:
\[ 37 - 4 = 33 \]
Now, to determine how many times he can ride the roller coaster, we know each ride on the roller coaster uses 3 tickets. We can find the number of times he can ride the roller coaster by dividing the remaining tickets by the number of tickets per ride:
\[ \frac{33}{3} = 11 \]
Therefore, Delon can ride the roller coaster 11 times.