Welcome to the forum!
The smoke unit in your locomotive would probably smoke better if you add more cars to make a longer train. This will make you turn up the power a bit more on the transformer, giving the heater element in the smoke unit a higher voltage. You can also try Lionel smoke fluid, available online if your dealer does not stock it. There are other smoke fluid manufacturers that you can use their product in your locomotive also. You may need to add 10 drops of fluid to get the unit to smoke more also. Hold the loco in one hand, and rig up your transformer leads to the loco; one lead to the front or rear truck, and the other lead to a pickup roller. Turn the power up and run the loco in your hand. See how it smokes with full power. If it smokes well, you may need to add more cars as suggested. If it still does not smoke well, it may be time for a replacement unit. Do try Lionel smoke unit first if your results are not satisfactory. You want to eliminate the smoke fluid as a cause of the problem.

The smoke unit in your locomotive is pretty much the unit that will work, unless you are handy, and are willing to modify the locomotive to put in a modern unit. I do not believe the smoke unit can be serviced, and is likely a sealed unit.

Larry