another thing to watch for are the ww 's that have mc-zn on them,they are a lead-zink mix and will act like you put a small amount of babbit in,i found that in my 100 lb melting pot 5% or moore of the mc-zn weights will give you fits,slow downs,stoppage blobs,the zink requires higher temps,and when they hit the cooler drippers the clog them up.ive gone to sorting all weights before casting ingots.(if they just say micro,p,al,mc,,, your ok,if they say mc-zn dont use them.the straight zink weights(fe-zn,honda) require 900+degrees to melt and will float to the top,watch your casting temp,keep it around 650 degrees)one thing to try when it happens is heat the bolt head(dripper) up with a blazer torch while running,and tap ladel,keep adding good lead untill you run it through,as far as dimples i find if i goofed up and left my brake fluid in the tank during humid weather it picked up moisture,after 100 lbs it usually burns out the moisture,thats why i try to drain my tank(15gallons harbor freight parts washer)after every run,i like the dot 3 because its free,and it rinses with water(get used stuff from service shops with brake flush equipment,so if your adding water cut back on it,mark jones