The pen shown is from a Classic American kit sold by Woodcraft. The pen is reminiscent of a Parker Duofold from the late 1920's and early 1930's. The color pattern is very similar to one used on Duofold pens.
Step 1: Making it flow if dried out
In more severe cases, as when ink has been left in a pen during several weeks of non-use, cup your hand under a faucet and fill it with water. Quickly dip the whole section into the water in your hand and remove it. Cap the pen and carry it in your pocket for an hour or so before using. If the writing is light in color, touch a facial tissue to the nib and feeder a few times to remove excess water or watery ink.
Fountain pens like to be used regularly. If you are not going to use a pen for a while, empty the ink from it and flush the pen with water until no discoloration from ink appears.
Do not mix inks from different manufacturers. They sometimes react with each other and form chunky, gelatinous material that clogs the ink passageways. Use fresh ink that has been tightly capped or fresh cartridges. Purists fill the air space in an ink bottle with an inert gas like nitrogen before putting the cap onto the bottle. They do this to keep the ink from oxidizing.