View Full Version : Anti-siphon valve??

05-05-2012, 08:17 AM
Is this something that all boats have, or just carbs? I have a GT40 with fuel injection. Someone told be to check the anti siphon valve when I mentioned that I have a very bad stumbling in the engine after only one pass. His was in the fitting at the top of the fuel tank, but my fittings on the tank are just plain brass 90 deg angles with brass hose barbs.

east tx skier
05-05-2012, 01:04 PM
Did you look inside of those fittings? An ASV is a coast guard required item so that if your fuel line breaks, the gas tank doesn't dump all of your fuel into the bilge.

I have a PCM GT40. The asv is on the barbed fitting on the fuel send line (might have some red tape on that line. Does your barbed fitting unscrew from the 90 degree fitting?

05-05-2012, 01:18 PM
Yes, I pulled the barbed fitting out of the 90 deg. No valves or balls of any type in there. I guess I will call MB SPorts tomorrow and see if they remember where they put them back in 98.

Table Rocker
05-06-2012, 09:09 AM
Another thing you should check is the fuel tank vent. If it is plugged, you will get a few runs in before it starts pulling a suction on the tank and your pump won't be able to pull fuel. After sitting a while the air will creep back in allowing a few more runs before you do it again. Try cracking the fuel filler open after it starts to give you trouble and see if it helps. It's just a shot in the dark, but during storage sometimes the vent outlet looks like a good home for some insects.

05-08-2012, 07:57 AM
Thanks Rocker, I did check the tank vent. It is clear

05-10-2012, 11:14 AM
I called MB Sports, and they can't remember where they put the anti siphon valve in 1998. Maybe it doesn't have one.

east tx skier
05-10-2012, 12:12 PM
Pretty sure it's a coast guard requirement. My boat is a 98 as well.