When you post some pictures, both general ones of the machine and specific ones of the clutch and belts, someone may be able to identify it for us micka. Meanwhile, I suggest you take a look at all of the White owner manuals, and see if there is a recognisable picture and description:
http://lawnandgarden.manualsonline....ite_outdoor_lawn_mower_product_list.html

The owner manuals also tell you how to make adjustments to belts and clutches, and include Illustrated Parts Lists, so if you can find the right one, it will probably solve your problems. Please come back and tell us how you go, including your actual model number, plus pictures of your mower and its belts and clutches. We have very little information on White products, and members will be interested.