I have a 2002 chaparral 183ss with a Mercruiser 4.3 Alpha1 carburated motor. I recently purchased this boat a month ago, and upon the test drive before me buying it the boat and motor ran perfectly. the seller said that they had not changed the oil in the motor this season yet, and that I should do that before taking it out. so a week later when changing the oil the motor ran fine while i was warming the oil up so that it could be changed. Two days later on Saturday morning I took the boat out for my first time on the water. It would not run! 45 minutes went by of me trying to get it to run and it just wouldn't. upon bringing the boat back home, and checking things and testing things, I found out that the electric fuel pump was not running. so I made some jumper wires and jumped the pump directly to the battery and the pump runs fine, it just doesn't run at all when plugged into the factory wiring harness. I have looked through the service manuel to see if there is some kind of fuse that's tied to the fuel pump and I cannot find anything of the such. upon searching throughout the boat for a fuse panel or fuse blocks there is nothing to be found as well. the only thing that I have is a black relay box under the driver's console, and none of those relays have anything to do with the fuel pump. so meanwhile I went ahead and hooked up a temporary toggle switch with a fuse block from the battery directly to the pump so that I could use the boat and it runs perfectly. also everything else on the boat works in perfect condition. all my gauges work, trim, battery, oil pressure, water temp, spedo, and tach, etc. so I am just mind boggled on why the fuel pump worked fine on thursday when changing the oil, and then come saturday it doesnt. please someone help me with this because the miss's is a little disturbed. also, i believe you should hear the fuel pump start pumping when you turn the key to the on position, we don't even hear that.