Originally Posted by donald2

can a bad CDI cause the fuel pump to be inoperative?

Originally Posted by dzzy

Sure seth22. First off you must have a good battery hooked up, gas in the tank and the fuel valve turned on. Unplug the fuel cut relay, you can't test it directly. Turn the key on and probe the black\brown and green for battery voltage, with green being the ground, you should have it. If not, check the fuse, and make sure the green wire has continuity to ground. If your voltage is good here, drain the carb (or your pump won't run period) via the flatblade screw on the bottem of the carb, leave it open and put a suitable container underneath the machine to catch the gas if you want. Bend a paper clip in half and short the black\brown and black\blue wires of the cut relay coupler. Turn the key on. Your pump should click and gas should run out the drain of the carb. If it doesn't run, go directly to the fuel pump bullet connectors on the right side of the airbox, make sure they're plugged in. If they are, most likely your fuel pump is faulty. You can also apply 12vdc directly to the pump to check it. The pumps CAN fail intermittently, sometimes if you tap it with the back of a screwdriver it'll start to work (for a while anyway). If the pump works when you paperclip those wires, you can assume your power supply and pump is working fine. The fourth wire to the cut relay is a black\yellow, which ends up at the cdi coupler. When the relay reads a signal on that wire, it closes the same ciruit you did with the paper clip. So...if you don't have the spark signal to the relay from your cdi, the pump won't pump. This signal is difficult to read with a meter. If you have spark, and your pump works when you clip the wires, unplug the cdi and the relay coupler and check for continuity between the black\yellow wires. If you have it, the fuel cut relay is bad. Whew...hope that makes sense.