Wednesday, December 15, 2010

Arctic Cat F6 Sno Pro

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?


1 comment:

  1. I am not having a no start problem but mine is sputtering and loading up with fuel at low speed & rpm and if driven like this will eventualy foul a plug but if you run it hard it seems like it is fine. Most info so far is that my fuel pressure is too high????