Ski Doo Everest, Clutch Problems

I figured it was time to test out our Vintage 340 Ski Doo Everest on breaking trail. Turns out it is in bad need of some clutching work. On the trail the clutch works very smooth and picks it's speed up quickly, but in the deep snow the belt just gets pulled into the secondary clutch and bogs the engine down...Giving more tension to the clutch should remedy this problem.