Wash potatoes throughly and then place in large pot. Add water to cover and place over medium heat. Bring water to a rapid simmer and continue simmering until potatoes are just fork tender. Large potatoes will take about 20 minutes until the center is tender.
Once potatoes are done, drain water and allow to cool for a little until they're cool enough to touch. Remove peels and then roughly chop cooked potatoes into 1" cubes.
In a large bowl, add mayonnaise, sugar, salt and vinegar and stir to combine. Add diced potatoes and diced onions. Stir until well combined.
Dice hard boiled eggs and fold into potato mixture.