Brand and size of anti-siphon fuel valve

[pwrobert]

I see there are anti-siphon and Check valves. It seems the are different and used for different purposes. <br />if I have 1/2” fuel lines what size anti-siphon valve should I install so that I don’t restrict the flow so much. That is should I install a 5/8” hose segment and use a 5/8” valve. <br />any particular brand?  It seems the one I purchased takes a pretty fair amount of blowing or sucking pressure when I try it by mouth. 

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[pwrobert]

I read about using them on an earlier post. I would only use one for my center tank which is mounted lower than the outboard ones. Top of center tank is about 10 inches below bottom of the others and the fuel will drain back if left a day or so between cranking. Normally I just turn off the supply vale when using it. <br />I don’t believe it’s return is made to go to bottom of the tank. It was built by a shop for me in 1998 and I did not specify. <br />other tanks I know do not but not an issue there. They are level with or above the engines. If it is a problem causer I’ll just continue as is. Rather not add any issues. Just something I thought I saw recommended on SB site once before. Thanks. <br /><br />

[Tony Athens]

Curious, Why do you need anti-siphon valves in the fuel plumbing? Are your retun lines submerged at all times  (close to the bottom of thr fuel tanks)  and none of your return system/lines/fittigs, etc  have any air leaks… You have mechhanical B’s, right?

Yes, anti-siphon valves they can be very restrictive depending on the design.

[Author]

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