REMOVAL/TESTING: If it is the standard connection type of pump, there is a simple slide lock holding the O-ring sealed inserts into the pump body where each hose is connected. Pay attention to which hose is where, so you don't swap "in" and "out". ("in" is the hose from the fresh water tank) The trick, if the pump is mounted to the underside of the helm floor, is to get the two screws out of the base on the side away from you that you cannot see. It can be done by braille method with some patience. There probably won't be enough wire to get the pump out of the heater opening. Note the wire colors and then cut, to be reconnected with waterproof connectors when finished. The pressure switch can be taken off without disassembling the pump. the pump head can be disassembled to be cleaned or have debris removed. the pump head screws are not all the same, so be sure you mark the location of each screw and the cover, or make a drawing. if there is not a filter on the intake side of the pump or in the intake line near the pump, debris may be making the pump leak back when it stops, making the pressure switch cycle back on when the pump stops. It is also possible the pressure switch may be failing, but you can't tell until you are sure the check valves (small rubber discs in the pump head) are not leaking back. After cleaning the pump head, reassemble the pump and pressure switch being sure the screws go back in the correct locations. I suggest you connect the hoses and splice the wires with wire nuts for a temporary test since the pump is so difficult to mount. If it now operates correctly you can go to the next step. If not, and you replace the pump, you will still have to do the next step.
INSTALLATION: If there is not an in-line filter upstream of the pump, obtain one and splice it into the intake hose. The reinstallation part should be easy, but it is not. First, find a piece of wood about 1.5 inches wide and about 9.5 inches long. I used a piece of 1/4" plywood. Make a "crutch" that you are going to stand on the inner hull under the pump motor so you will be able to wedge it in place to hold the motor base up to the mounting surface. If reinstalling, once you get one of the screws which you can see started. then you can get one of the screws on the blind side started. Repeat until installed, then properly reconnect wires with waterproof connectors. If you are putting in a new pump and it has an integral filter, one less step. If the mounting screws line up with the old holes you can do the preceding. If not, then a little extra work to get screws started in new locations is required. You can still use one of existing screws and screw holes to start the mount of the new pump.
You may be able to tell I have some experience with this.
