View Full Version : Anti-siphone valve repair

08-10-2012, 05:59 PM
Boat acts like it is starving for fuel 2001 Outback

When I started working on it, I changed the fuel filter/water strainer becuase it hadn't been changed for a while. Tried to start the motor, and it started and died within a couple of seconds. I cycled the fuel pump numerous times, still nothing. I pulled the filter I just installed, and it was dry as a bone. I placed a container under where the filter screws on, and without the filter installed, cycled the pump a few more times - nothing for a while, then just a little burp of fuel came out.

Time to start trouble shooting - to make sure the pump was good, I disconnected the 3/8" fuel line from the pump, and connected a 3 ft length of 3/8" fuell line to it, and then stuck the other end of the fuel line in a 1 gallon gas container - cycled the pump, and BAM - lot's of fuel came pouring out. Re-intalled the filter, prime the pump a few times, the tried to start the motor again - started right up and ran great.

So that told me the problem was from the fuel tank to the fuel pump. To make a long story short, I ended up removing the intake nipple from the tank - it has an anti-siphon device built into it - basically a spring loaded check ball to allow fuel to flow to the motor, but not back to the tank. There was a bit of corrosion built up on thr inside of the nipple, causing the check ball to stick in the closed position, and not allowing any fuel to go to the pump. I cleaned it up with some WD-40. With the check ball moving freely inside the nipple, I re-installed the nipple, and the fule line. Cycled the pump a few times to get the line full of fuel, then started the motor. It fired up, and I let it run for about 20 minutes. Didn't show any signs of stalling at all.

To access the fittings at the tank on my LS, I had to remove the rear most panel. 4 screws along the bottom, and 6 at the top.

I haven't had a chance to get it out to run, but I'm pretty sure this was the cause. So, it might be something to check out before going out and buying a fuel pump. ;)