fuel anti syphon fitting?

[PiratePast40]

My 76' Fiberform I/O did not have modern fuel system components so I'm piecing together a new system by replacing the leaking steel tank and adding a separator/filer assembly. The tank is elevated in the closed bow and not below decks so I'm concerned about the possibility of the tank being syphoned into the engine compartment in the event of a leak. I've seen some fuel line barb fittings that are called anti syphon devices. Since I have no reference,what diameter fuel line should I be using and where should the anti syphon fitting be located - at the tank suction point or back aft near the engine? I'm assuming that these are similar to a relief valve and will only open under a certain amount of negative pressure.

Is the anti syphon fitting supposed to be a part of the tank? Here's the tank I've ordered: http://www.iboats.com/19_Gallon_Fuel_Tank_26_L_X_16_W_X_11_75_H/dm/*******.114415654--**********.019535396--view_id.484667

 

[HT32BSX115]

Re: fuel anti syphon fitting?

Howdy,

Yes that fuel tank being higher than the engine would need to have an anti-siphon valve to be USCG compliant.

Although I think it's mainly a manufacturer thing. You (the owner) legally don't have to add one.

It would be a pretty good idea to install one anyway.

You'll need one like the following from West Marine

Put a 90 degree elbow in the tank and screw the fitting above into it.

Use a good thread sealant on all pipe connections.

It's just s simple check-ball with a spring against it. The fuel pump provides enough suction to overcome the spring but a simple siphon will not.

Since this is an older boat you probably should replace the fuel line from the tank to the fuel pump too. (the fuel line from the fuel pump to the carb should be steel)



Use USCG rated hose like the following (from West Marine again)

They do have different size hose. Just make sure you get the correct size to match the fitting.

West Marine usually has it all in stock hanging on the shelf.


Regards,


Rick

 

[capecodder116]

Re: fuel anti syphon fitting?

anti-siphon valves are usually available in 1/4" and 3/8" NPT (thread dia) X 3/8" hose barb. Can find the valve at West Marine for under $20.00 make sure to use Coast Guard approved 3/8" fuel line with and double up on the stainless steel hose clamps and do not overtighten the clamps. Also, do not use any sealant tape on the fittings threads.

 

[PiratePast40]

Re: fuel anti syphon fitting?

Thanks guys.
Just a couple of more questions:

Why not teflon tape with gas (I'm assuming that's meant you meant about tape)? If not teflon tape, is there a certain type of pipe dope that should be used with gasoline and the pipe threads?

It seems that the anti syphon fittings are aluminum and other fittings are brass or copper. Is it ok to mix and match aluminum and brass fuel fittings?

 

[HT32BSX115]

Re: fuel anti syphon fitting?

Thanks guys.
Just a couple of more questions:

Why not teflon tape with gas (I'm assuming that's meant you meant about tape)? If not teflon tape, is there a certain type of pipe dope that should be used with gasoline and the pipe threads?

It seems that the anti syphon fittings are aluminum and other fittings are brass or copper. Is it ok to mix and match aluminum and brass fuel fittings?

Use a good thread sealant on all pipe connections.

Yeah, I should have been more specific.......use a good sealant (NOT T-Tape) Which can and does leak in fuel fittings.

Use something like Pipe Joint Compound from Permatex that is RATED for fuel fittings.




Regards,


Rick

 

[180shabah]

Re: fuel anti syphon fitting?

Just a couple quick things - as the owner it is your responsibility to maintain USCG compliance of all systems, and that does include using an AS valve. Also, there is no requirement for the fuel line from the pump to the carb to be steel. It is just a better solution. You can use the "rubber" line as long as it is A1 and you also use the correct barbs and clamps.

 

[HT32BSX115]

Re: fuel anti syphon fitting?

Also, there is no requirement for the fuel line from the pump to the carb to be steel.

Actually there is. I just didn't see the "or USCG A1" as an alternative.

Those USCG regs are for Manufacturers though. I haven't found anywhere that indicates that the owner of a pleasure boat not used for hire absolutely has to keep his boat in compliance with current regs. (although it would be smart to do so for liability reasons........)




From:33 CFR 183.501-590

? 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 ? 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 of 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.

In any case, It is smart to install the anti-siphon check valve and replace all your fuel hoses with new USCG A1 hose. some of those antisiphon valves are aluminum. Be very careful when you tighten it. They break very easily. (I know from experience!!)

 

[PiratePast40]

Re: fuel anti syphon fitting?

I believe that many of the regulations were written because people got hurt or hurt others. I agree completely with making everything reasonably safe and using the regs as a guide even if they don't have callouts for requirements for pleasure boats.

That was the reason behind my inquiry in the first place - safety and not necessarily the regs.

 

[havasuboatman]

Re: fuel anti syphon fitting?

I believe that many of the regulations were written because people got hurt or hurt others. I agree completely with making everything reasonably safe and using the regs as a guide even if they don't have callouts for requirements for pleasure boats.

That was the reason behind my inquiry in the first place - safety and not necessarily the regs.

I wish more folks had your common sense. I see about 5 burning boats a year on the lake here. (Havasu) I have yet to hear of one that common sense and following basic start-up proceedures wouldn't have prevented.

 

[180shabah]

Re: fuel anti syphon fitting?

Actually there is. I just didn't see the "or USCG A1" as an alternative.

Guess my response was a little misleading. If you use a metal fuel line then, yes, it must be steel, not copper, aluminum, etc. However, the A1 is an acceptable subtitute for any portion of the line from the tank to the carb inlet. Also worth noting, A1 must be used as a strain relief at any point you transfer from one "structure" to another. ie from engine to remote fuel filter or from engine mounted filter to the primary fuel line. The vibration and movement will fatigue a hard line quickly, then BOOM!

 

[Howard Sterndrive]

Re: fuel anti syphon fitting?

every old boat I've owned had a copper fuel line. One is 45 years old.
I wonder what's wrong with copper. Seems way better than rust prone steel.

 

[PiratePast40]

Re: fuel anti syphon fitting?

I'll be using rubber hose from the tank back to the filter and then another rubber hose jumper to the fuel pump inlet. I really wouldn't have thought of all metal lines since my pipe bending and double flaring skills are a little rusty . And yes, using the rubber hose as a strain relief makes perfect sense.

I want to do it right but don't want to unnecessarily jump up to the next quality level.

 

[180shabah]

Re: fuel anti syphon fitting?

Sounds like you got it under control.