By how much does daylight time vary at the equator?

The answer is printed over the Pacific Ocean on most world globes in the form of a figure 8. It shows the variation in solar noon because of the eccentricity of Earth's orbit. The days are very slightly longer when the Earth is closer to the sun and therefore orbiting faster around the sun. The variation in the length of a day at the equator is the angular change on that figure 8 from one day to the next divide by 15 degrees times one hour.