Today I worked on a 2010 Arctic Cat F6 Sno Pro. The owner brought me the machine because it would not start. He suspected a fuel problem (normally I don't listen to what the owner says, but this time he got it right). I pulled the rope a few times and the engine did not fire. I pulled the spark plugs and checked for spark, then squirted a little fuel in the cylinders. This time when I pulled the rope it fired up for a couple of seconds. Definitely a fuel problem.
This machine has a modern engine with a battery less fuel injection system. When you pull the rope the stator makes enough electricity to charge a capacitor and run the injection system. I pulled the fuel line off the injector rack and checked for fuel pressure when pulling the engine over. There was no fuel pressure so I decided to check the voltage to the fuel pump. I found the wires going to the pump and checked for voltage when cranking. I saw spike of 15 volts when pulling hard on the rope and it then gradually dropped off. All these signs point to a bad fuel pump.
The pump is mounted inside the tank very much like a typical automotive system. Just like working on cars, it is a pain to get to the pump. I decide that I would like to do one more test to make sure it was the pump before I pulled everything apart. In the photo you can see my temporary fuel system that I rigged up to run the engine. I have a "Hudson" type garden sprayer filled with gas, I pumped this up to 15 psi (thanks Dave for the help) and connected it to the fuel rail using a few plumbing fittings and tubing. With this setup supplying the fuel pressure the engine ran OK. I later learned that the system is supposed to run at 40 psi, but 15 was enough for testing in the shop.
Once I was sure that it was a bad pump I pulled everything apart and took the pump out of the tank. Now I just need to find a replacement. The Arctic Cat dealer only sells the complete pump assembly with the mounting bracket and fuel level sensor attachment for $450! The pump itself is a basic Walbro like automobiles have, normal price $80 -$100. Hopefully I can find a source that will sell me just the pump. Any one have any ideas where to look?