Anti-syphon valve

[kamby]

Not sure if im in the right forum section or not.

I need to get a new anti-syphon valve for the fuel tank, the one on it now is a 3/8 barb 3/8 npt or moeller part number 033802-10 its the one that looks closest to the one i have

Moeller states that it crosses over to a tempo 260030 but tempo lists that one is a 3/8 barb 1/4 npt


The measurements on mine are 3/8 barb, and the fat part on the threads is about 1/2". Is that the right tempo part number?


Mine went out and it drains back into the tank quickly. Boat is a 1985 Bayliner capri 1950 BR. Has a 28 or 38 gallon tank (forget which size)

Thanks

 

[HT32BSX115]

Re: Anti-syphon valve

"Give a man a fish and he will eat for a day. Teach a man how to fish and he will spend all day in his boat fishing and drinking beer."

Now that's not true!...... I don't need to know how to fish to drink beer all day in the boat!!!

Did you already buy that fitting and it doesn't fit?

 

[JustJason]

Re: Anti-syphon valve

My grandfather taught me how to fish.....
I taught myself how to drink beer

If your fuel tank is above your fuel pump... then you need a new antisiphon valve. Just take it out and go to a dealer or west or someplace and match it up.

If your fuel tank is below your pump (which it sounds like if you say your lines are draining, and i'll touch on that more in a second) You do not need the valve and a simple brass barb from home depot plumbing section is fine.

Your lines shouldn't be draining, and that is not the point of an antisiphon valve. If your lines are truely draining then you have an airleak in one of the many fuel line fittings someplace or the valves inside of the fuel pump are bad and leaking.

You can test the lines and the pump by following the test here...

http://forums.iboats.com/showthread.php?t=283269

 

[kamby]

Re: Anti-syphon valve

The tank is below the pump. I was wondering about the antisipon valve as i looked at another boat and noticed it didnt have one; same setup pump above tank just a v-8 not a 4cyl. Even same tank model number as mine.

I'll try it without the anti-syphon on it, i have the bayliner manual but it doesnt mention it in the book.

Thanks for the link one of those guages is on my list, as well as a compression tester.

Without some kind of anti-siphon or check valve wont it always drain the fuel lines out? Without the restriction of the anti-siphon it should pump it back up quicker right? In general im not this dumb, i just dont want the boat to explode on me by having an in correct fuel system, im changing the fuel hoses out with new marine hose and putting in a fuel water seperator; come to find out there is not 1 fuel filter on this thing.

Also i cleaned the carb out and noticed the shut off valve was sticking either open or close, a little pice of debri got into it (gee i wonder why).

 

[HT32BSX115]

Re: Anti-syphon valve

The anti-syphon valve is only required if any part of the fuel system (including the fuel line) goes BELOW the tank.... (it's a USCG... actually, Federal Law to have it and manufacturers are required to install them)

Here is the text if you're interested....
http://edocket.access.gpo.gov/cfr_2004/julqtr/33cfr183.568.htm


Now having said all of that it is STILL a good idea to have an anti-syphon valve installed



Cheers,


Rick

 

[Silvertip]

Re: Anti-syphon valve

The purpose of the anti siphon valve is not to prevent fuel flowing back to tank, but rather to prevent fuel flow toward or into the engine should there be a fuel system failure. A leaky inlet needle for example could allow fuel to siphon into the engine filling it up with fuel. A leaky fuel line that droops down lower than the level of fuel could fill the the bilge with fuel. You do not likely have a bad valve. You could have a bad primer bulb. There are valves in it that help prevent drain back. But generally there is enough fuel in the carb bowls that allows the engine to start and refill the line. If you squeeze the bulb and it is soft after an engine has been run, that's normal. Once running, fuel is sucked through the bulb and line so there is a slight vacuum -- not pressure.

 

[JustJason]

Re: Anti-syphon valve

You could have a bad primer bulb

Whaaaa????? Forget what forum your in Silvertip?

The last time I saw a primer bulb in a sterndrive I laughed.... Actually I see a few a year... Have no idea who put them in or why they are there.

Kamby... Like I said earlyier. Its the valves in the fuel pump that keep a vacuum on the lines when the engine is not running. If they are leaking then no have no vacuum. Bad pump or air leaks in the system.

 

[kamby]

Re: Anti-syphon valve

Whaaaa????? Forget what forum your in Silvertip?

The last time I saw a primer bulb in a sterndrive I laughed.... Actually I see a few a year... Have no idea who put them in or why they are there.

Kamby... Like I said earlyier. Its the valves in the fuel pump that keep a vacuum on the lines when the engine is not running. If they are leaking then no have no vacuum. Bad pump or air leaks in the system.

Ok makes sense, now the more you explain it the more i understand. It could be a weak fuel pump, mines has the puke tube on the pump and i never noticed any gas running form it to the carb, indicating faulty pump. i noticed the drain back when i was running the engine of the jerry can last fall winterizing it while i was cleaning the tank. Typically the boat starts pretty easy if u start it every other week, if you let it sit for a month it takes a bit and the carb bowl is empty, no gas in oil and no gas pooled into the intake.

I have sen a primer bulb on a stern drive before, asked teh guy and he says he uses it to prime the engine/ carb if its been sitting a while. Once it running good he disconnects it and hooks the fuel pump back up.

Thanks for all your help guys, i'll let your know the results when im done with the tune up this weekend, for being May our weather has been somewhat chilly.