The outer surface of smoked foods can end up tasting pretty bad if the wood used for smoke burns too cool, or if too much wood is used to smoke the meat. Using wood that's not completely dried and cured, or green wood can cause that nasty taste too.
If you're seeing thick, dense smoke coming out of your smoker, it's a sign of this problem. Try the following to get rid of the foul tasting smoked meat.
Use only dry wood. If using chips, soak them in water if you place them directly on top of the charcoal. If you wrap wood in foil first, there's no need to soak it first.
Try using less wood, especially in an electric smoker. Electric smokers are typically sealed up fairly tightly since there's no need for airflow to keep the charcoal or wood fuels burning. A fist sized chunk of smoker wood, split into two or three pieces, added one at a time is usually plenty in an electric smoker.
Using a wood fired smoker? Use a smaller fire and keep it burning hot, and not just smoldering. A smoldering fire creates a lot of creosote. Creosote blackens food and has a bitter, tongue numbing quality, and an almost chemical like taste...nasty stuff.
Smoke exiting a meat smoker should be very pale and almost invisible. If the smoke is dense and bellows out of the smoker, you're overdoing it.