We just bought our boat in November, so we're not entirely certain how the systems are supposed to work, but it just doesn't seem like the head is bringing in enough raw water for a proper flush. The Wilcox-Crittenden Head Mate that we have brings in outside water when the lever is in the flush position (vs the "pump out" position). The water that comes in only trickles down around the edge of the bowl. Also, the water is washing little black particles into the bowl (more at first than now), but I don't know if that is just residue from under the rim (the boat had been sitting on the hard for 2 years before we bought it) or if it's indicative of a more serious problem. To my knowledge, there is not a strainer on the intake line or through hull. Could we have a clog in the line? If so, how could we flush it out? Or worse yet, is a trickle the most we can expect out of a marine head?Thanks in advance,Dana