In general, you shouldn't worry about Encumbrance. Characters will usually carry no more than their characters think they actually need. But occasionally it may become dramatically important–such as during a chase or when attempting to lug a heavy treasure away from a roaring dragon! When that occurs, use the guidelines below.
A character can carry five times his Strength die type in pounds without incurring any penalties. This is called his “Load Limit.” A character with a Strength of d8, for example, can comfortably carry 40 pounds. (Ignore normal clothes when figuring weight.)
Carrying too much weight inflicts a -1 penalty for every additional multiple of your Load Limit. The penalty applies to all Agility and Strength totals, as well as skills linked to either of those two attributes.
A hero with a d8 Strength, for example, has a Load Limit of 40 pounds. He can carry 41-80 pounds at a -1 penalty to his Strength, Agility, and related skill rolls. He could also carry 81-120 pounds at -2, or 121-160 pounds at -3.
Characters cannot regularly carry weight that inflicts a penalty of more than -3. They may be able to lift greater weights (up to a -4 penalty) for a few short steps at the discretion of the GM, however.
Savage Worlds Deluxe Edition p. 55