Mercury 2-4-C grease is not the best grease for wheel bearings, the best thing to do is have both hubs overhauled, check the bearings, replace the grease seals, spindle wear sleeves (if required) and use a proper grease like Lucas Marine grease or Lubrimatic Marine trailer wheel Bearing grease, both are Calcium Sulfonate based. Over greasing your hubs is how grease seals are ruined and allow water to penetrate the hub. I just give the grease gun 1-2 pumps to move the plunger out about 1/8 of an inch, once or twice a year.