It sounds like a tire spinning on the rim. If it pulls right on acceleration and pulls left on braking, it's a sign that one of your right tires is spinning on the rim. A couple drops of CA to secure the tire to the rim will correct it.

If that wasn't the problem, another possibility is having higher resistance in one (or more) of your outdrives. It could be a bad bearing (or bushing). To check for resistance, turn each tire by hand. They should feel the same. If one is harder to turn, check the bearings for the in the hub, the axle itself, and the bearings supporting the differential.