Anti-Siphon valve

[looseplay]

Any tricks on pulling the anti-siphon. I have a 1996 5.7 mercruiser in a stingray cudy. Very little room there to work with and before I go nd start loosing bolts and puling tubes I cant see just waned to get any ideas. I know its a fuel related problem I am having since I ran on external tnk yesterday. While I have it out I am going to drain tank. Thanks

 

[Brentathon]

Re: Anti-Siphon valve

They're usually just tapered male pipe threads (MNPT). Maybe 1/4" or 3/8".....?

 

[EddiePetty]

Re: Anti-Siphon valve

...assuming the fuel pick-up is in the aft end of the tank:

Secure ALL electrical power in the boat either by disconnecting the batteries or opening the selector switch.
Set the hull bow-down to lower the fuel level at the pick-up.
While you have your hands on the anti-siphon valve, go ahead and remove the pick-up tube to inspect for debris/deterioration.
Use Loctite Thread Sealer on all threaded connections during reassembly. (teflon tape is kinda iffy on fuel connections)

 

[looseplay]

Re: Anti-Siphon valve

Thanks for the info, new to repairing on my own, I can feel a hex nut, do I un-screw that and the siphon just comes right out?

 

[EddiePetty]

Re: Anti-Siphon valve

Apparently you have at least an access plug over your pick-up connection (and hopefully one over your fill and vent connections). If you have the full cover access plate over the tank, life will be so much easier if you remove the complete cover to access your fittings.
To answer your base question: Normally the anti-siphon valve has a hose barb on the down stream end hose clampled to the fuel line. After removing the fuel line (hose), normally the anti-siphon is simply un-screwed on the up stream from the pick-up fitting, via a hex. A mirror and strong light my help you out!!