do i need an anti-syphon valve

[suzukidave]

i just realized today i have one.

i am replacing the fuel line and resealing the hatch so i need to decide. tournament 223. tank is in rear.

 

[seasick]

i just realized today i have one.

i am replacing the fuel line and resealing the hatch so i need to decide. tournament 223. tank is in rear.

If any portion of the fuel delivery system, hoses, fittings, filters motors etc, are lower than the fuel level in the tank, then an anti-siphon valve is needed to protect from fuel pouring into the bilge if a fitting or hose leaks. Also note that depending on the angle of the tank at a given time, the effective fuel level in the tank can be higher than the level of the pickup fitting. The bottom line is that the safe approach is usually to include the valve.

 

[DennisG01]

CG requirement for the reasons seasick mentions. I would imaging that IF you even had a related issue and filed an insurance claim and IF they found out there was no valve, you would be hard pressed to get a payout. Loss of life, of course, is much more serious. Best to keep it there.

 

[suzukidave]

thanks. the comment about a leak in the fuel lines makes good sense.

i cannot source a new anti-syphon valve anywhere here on a timetable of this week (i live far from the ocean) so i will cross my fingers and reuse the old one.

 

[gw204]

I don't believe it's required on a outboard powered boat...but don't quote me on that.

 

[DennisG01]

That's a good point, Brian. I "thought" it was required when there was a built in tank, below decks -- as well as an enclosed (stern drive) engine? But now I'm not positive, either. Either way, sounds like a pretty good thing to have. If not for the safety feature, then to avoid the 5-figure fine for pumping gas overboard (which is what would happen when the bilge kicks on). And back to the safety thing, assuming the bilge pump doesn't happen to make a spark. Although, it shouldn't...

 

[DennisG01]

A quick Google search found this on http://www.uscgboating.org:

FEDERAL LAW

183.568 - Anti-siphon protection

Each fuel line from the fuel tank to the fuel inlet connection on the carburetor must:

(a) Be above the level of the tank top; or
(b) Have an anti-siphon device or an electrically operated fuel stop valve:

(1) At the tank withdrawal fitting; or
(2) Installed so the line from the fuel tank is above the top of the tank; or

(c) Provided that the fuel tank top is below the level of the carburetor inlet, be metallic fuel lines meeting the construction requirements of Sec. 183.538 or "USCG Type A1" hose, with one or two manual shutoff valves installed as follows:

(1) Directly at the fuel tank connection arranged to be readily accessible for operation from outside the compartment, and
(2) If the length of fuel line from the tank outlet to the engine inlet is greater than 12 feet, a manual shutoff valve shall be installed at the fuel inlet connection to the engine.



"Anti-siphon protection" is a term applied to the means of preventing the siphon action of permitting fuel to continue to flow out of the fuel tank in the event there is a break or rupture in a fuel distribution line, or if a fitting in the fuel line loosens, creating a leak.

"Anti-siphon protection" may be accomplished by one or more of the following methods:

(a) Keep all parts of the fuel line from the fuel tank to the fuel line connection at the carburetor above the level of the top of the fuel tank. The tank top level is determined with the boat in its "static floating position." Practically, the fuel pump and fuel filter(s) must also be above the tank top.

(b) Install an anti-siphon device at the tank withdrawal fitting. The fuel distribution line may then run below the level of the tank top. A filter may be installed between the fuel tank withdrawal fitting and the anti-siphon device.

 

[TUNAHUNTER197]

Real simple answer her. No for outboards, yes for inboards. I have since removed mine and installed a thread to barb fitting without the ball and spring. Sooner or later it will gum up and cause fuel issues.

 

[suzukidave]

so thinking about this further.

i can run all my fuel line above the top of the tank except for about a foot where it passes through the bilge bulkhead where it would be slightly below the top of the tank. there are no fittings that could fail anywhere near lower than the fuel tank and i can strap all the fuel hose in place in the bilge so that even if it was cut it would not droop below the tank level.

so the only protection i would get from the valve would be to prevent overflow of a full tank if the fuel line was to leak between the pickup tube and the point on the other side of the bulkhead where it goes up. i suppose a little bit could also syphon out if i filled the tank so high that it went up the fill tube.

given the risks of the valve causing fuel starvation it does not seem worth it.

 

[DennisG01]

Usually these valves are good for, literally, decades. It's extremely rare that one goes bad in only 5 years. I wouldn't let that part enter into the equation. I've worked part-time/full-time in the marine industry for almost 25 years and am contributor in a very large (25,000 plus members) and active Sea Ray forum. I could probably count on one hand how often these go bad... and have fingers left.

As far as the OB vs IO thing... I tried my best to find any legal information about that and couldn't. If you have something to back-up what you wrote, please provide as I would be interested to read it.

 

[Meanwhile]

Last year my buddy boat had to cancel a tuna trip, one motor shut down. Yup, a bad anti-siphon valve. He went to check the other at the yard and it broke off when he touched it. My 2005 boat had issues with the anti-siphon valve and corrosion.

I think it depends on the amount of salt water allowed near the valve and how long it sits. My last boat was bad in that respect. I don't have much salt on top of my tank after one season so I'm hoping Grady's are tighter than others in that respect.

If not taken off, just inspect regularly.

 

[bayrat]

It cost about $10 and is simple to replace. Irregardless of explosive possibility , Dennis makes an excellent point of EPA liability if your bilge pump starts throwing raw gas into the water…think its $15k minimum fine. Lets see, $10 or $15k…hmm. If the lawsuits start to fly, wouldn't you want to be on the right side of the fray having the same equipment that the boat was designed with? If you are worried about the valve clogging you can always change it out every 5 years (or every year). JMHO.

 

[suzukidave]

i found a moeller brand a-s valve online that ships inside canada.

the pickup tube i ordered is the wrong one and i can't leave the coffins open any longer with all the rain and snow soon so i am going to tape up the hatches for now and deal with this in the spring. i will order a new anti-syphon valve and a regular 3/8 barb fitting and see how i feel.

now that i have breathing room i think i will also replace the fuel sender with a wema unit. heck, i might even get an auxiliary tank.