What are you smoking them on? I've done one on a Brinkmann smoker similar to this ...

...and it was a PITA because the charcoal bowl would fill up too fast and with the water bowl right above it, it was difficult to remove any buildup of ash. I got it to work and it was good.
But the second time, I used my Weber kettle grill like this...

..and it was so much better and easier to use. I have a grate that is hinged on both sides and have two charcoal baskets (one on each side). I have a drip pan that I put in between them and pour some applejuice in it. Speaking of that, I use a rub, but only put it on it for about 30-60 minutes before smoking. I also inject appple juice into it.
Here's the recipe and instructions below that I use. Works great and tastes good. If you put the rub on and let it sit overnight, you might find it to be a bit spicy. You can cut out or cut down on the cayenne.
Ingredients:- Boston Butt – about 8-10lbs of pork – pick one with the bone in
Then you will need a rub for your butt made up of:
- 4 teaspoons salt
- 4 teaspoons garlic powder
- 4 teaspoons onion powder
- 4 tablespoons paprika
- 2 teaspoons cumin
- 3 teaspoons black pepper
- 1 teaspoon cayenne pepper – a little more if you like your butt with a little kick
If you want to have more of a sweet flavor to your butt, you can add to the rub mix
- 5 tablespoons of dark brown sugar
Adding brown sugar gives the meat a sweet taste, but will also cause the meat to turn a dark color as you cook it as the sugar caramelizes. Cooking without the brown sugar results in more of a salty flavor and the meat will be a deep red color. It is just a matter of taste and what you like.
Mix all these ingredients together as the rub for your smoked Boston Butt. This will store for weeks in an airtight container in your refrigerator.
Cooking Instructions1- Apply a thin coat of mustard to the butt. You can use the cheap stuff or if you like it a little more tangy, use dijon mustard. The mustard provides some flavor, but also provides a base for the rub to stick to.
2- Generously rub your butt with the rub recipe above. If you plan ahead, you can wrap it up and let it sit overnight in the refrigerator to allow the spices to penetrate the meat.
3- If you prefer, inject your smoked Boston Butt with apple juice to add flavor and to keep it moist as you cook
4- Heat your BBQ to 225F degrees and put your butt on the grill. Indirect heat works the best and add your favorite soaked wood chips to add the smoked flavor
5- Plan on cooking the smoked Boston Butt about 60-90 minutes for every pound in the roast.
6- Every 2 1/2 hours, open it up and turn the roast to ensure even cooking. Mop your roast with combination of apple juice and olive oil to keep it moist
7- The meat is done when the internal temperature is above 190F degrees. The lower you keep the temperature, the more moist the meat will be.
8- Don’t be afraid to start early because it can take longer than expected. If it gets done early, you can always wrap it in foil and put it in a cooler. It will keep warm for hours after it is done. At least let the smoked Boston Butt sit for about an hour after you take it off the grill so you don’t burn your fingers as you pull the meat.
9- Serve with your favorite sides, salads, and drinks.