Anti-siphon valve

[mpritch272]

I replaced the connector at the top of the fuel tank with a quick disconnect- so I could swap in a 6 gallon tank for decarbing, etc.

The one I removed appeared to be an anti-siphon valve, does the quick connector have anti-siphon functionality built in? If not, could I get an inline anti-siphon valve?

 

[ezeke]

Re: Anti-siphon valve

The anti-siphon valve is to prevent the fuel from being siphoned from your tank in the event that there is a leak in the system or at the engine. If the sytem and engine are above the tank, the valve is not required. If any part of the system or the engine are below the top of the tank, the valve should be replaced.

There would be no fuel restriction after the anti-siphon valve that would prevent siphoning from completely draining the tank.

 

[mpritch272]

Re: Anti-siphon valve

I understand.

Does the quick connector have anti-siphon functionality built in? If not, could I get an inline anti-siphon valve?

 

[HighTrim]

Re: Anti-siphon valve

The quick connect will not have a one way valve in it, your fuel primer bulb does though, and usually prevents the backwards flow of fuel to your tank. Alot of guys remove the anti syphon valve absolutely, so I would not worry about it, especially if the motor is above the tank as Ezeke stated.

 

[ezeke]

Re: Anti-siphon valve

Unfortunately, the fuel system needs to allow fuel to flow out easily and therefore does not restrict in that way. You could place a anti-siphon valve in the line, but it should always be above the top surface of the tank. To meet the coast guard requirements, it needs to be where it was. Remember that the function of the valve is to keep the fuel from flowing out of the tank when conditions would otherwise allow it.

 

[mpritch272]

Re: Anti-siphon valve

Unfortunately, the fuel system needs to allow fuel to flow out easily and therefore does not restrict in that way. You could place a anti-siphon valve in the line, but it should always be above the top surface of the tank. To meet the coast guard requirements, it needs to be where it was. Remember that the function of the valve is to keep the fuel from flowing out of the tank when conditions would otherwise allow it.

How does it "know" the difference between fuel coming out during normal use and fuel coming out otherwise?

 

[ezeke]

Re: Anti-siphon valve

The test of proper function of the anti-siphon valve is that gravity will not pull the fuel through the valve, hence "anti-siphon". Otherwise, a fuel line with bulb and the engine end fitting removed should allow you to siphon all of the fuel from your tank once flow is established.