Completed water pump job a week ago. When boat was resting in water, engine would pump water and keep engine cool from startup. Previous Tech had removed tstats - Idle head temperature was about 104 degrees. continued to work on other issues thru out week and as week progressed by Friday I was having to raise neutral rev arm to get engine to start pumping water Once flow is started she continues to flow and pressure thru tell tale increases as rpm increases engine now idles at 114 degrees. This is the 3rd pump in 2 months - first for me to install. If I put flush on (ears) and drop her in water she pumps water right away. If I remove flush and drop in water today she will only pump with neutral rev arm pushed up. <br />Possible circumstrances: <br />This is a 21' Shallow Sport with Tunnel and Jackplate. Jackplate is frozen at highest position. When engine is trimmed against transom water intakes are below the surface of the water, but by only a couple of inches. Further more, this boat has a unifit cavitation plate that encompasses the entire lower unit. At start up exhaust rolls up against transom and exits water. Could water intakes be sucking this exhaust?, Could pressure release valve be sticking open?<br />Poor guy has already stuck out better than $800.00 for three pumps. My gut feeling is that the jackplate is the culprit, but if not he is going to be out another $500.00 and still smoking pumps<br />Appreciate your help <br />Ed
