Just put boat in water. I have two heads on boat. When I flushed fwd head, no problem, started right up. When I tried aft head, couldn't get any water to flow. Removed hose from inlet to bowl and filled with water and reassembled, nothing. Loosened hose to inlet of motor and it started to leak, so I'm assuming I have water up to motor. System worked when I put it up for winter. What is the problem? Is pump shot?