Well it could be flooded, I have a 601 as well (have had it since 2009). What I suggest is taking out the battery and removing the cartridge and mouthpiece, then blowing really hard through the battery section with the jewel cap removed. This should blow out the liquid should there be too much. If its too dry, drip one or two drops right on the bridge of the atomizer and try again. The 601 also has a built in cleaning feature, look at the terminals when the battery is in and you'll notice two small brass contact points. Touch both points with a metal object such as a butter knife and the red LED will light, the coil is now lit and you are dry burning it clean. Don't overdo it because it can burn out if left too long. Another thing to consider is that the DSE 601 is known to have many problems so dont leave it unattended with a battery installed, there are many times that vapers have reported the pipe activating on its own and burning out completely. Some say that the pipe will do this "cleaning cycle" on its own on purpose but I just see it a s a fire hazard.
Hope that helps, I still enjoy my 601 on occasion but its lack of performance and sketchy nature is the reason it only gets used once and awhile. I also remember that the break in period for the atomizer took a solid 3 to 5 days of constant use, I remember it tasting like a burnt tire but she plumes once you get past the nasty break in period so dont give up yet
PM me if you need more advice.
Neon
