anti siphon valve

[studders]

Hello to all, I have a quick question and I'm not even sure that I am in the right forum but here it goes. I have a mercruiser 3.0 and I was told that the anti siphon valve was bad and needed replaced. I have been searching for quite some time now and all I see I'd the valve barb. Pretty sure that is what I need. However is there suppose ti be a ball, spring and sleeve in there? If not how does the valve go bad if there is nothing there. The reason I was told it needed replaced is because when I am at wot I start to lose power and then I settle it down into neutral or slow down for a second then back to wot its fine. Doesnt do it all the time but it still does it. Could someone please explain and if all possible send me a pic of what that valve looks like so I'm sure of getting the right part. Thanks again for any replies and help.

 

[Bondo]

Re: anti siphon valve

Hello to all, I have a quick question and I'm not even sure that I am in the right forum but here it goes. I have a mercruiser 3.0 and I was told that the anti siphon valve was bad and needed replaced. I have been searching for quite some time now and all I see I'd the valve barb. Pretty sure that is what I need. However is there suppose ti be a ball, spring and sleeve in there? If not how does the valve go bad if there is nothing there. The reason I was told it needed replaced is because when I am at wot I start to lose power and then I settle it down into neutral or slow down for a second then back to wot its fine. Doesnt do it all the time but it still does it. Could someone please explain and if all possible send me a pic of what that valve looks like so I'm sure of getting the right part. Thanks again for any replies and help.

Ayuh,.... Welcome Aboard,.... At the tank's outlet, the fittin' the hose attaches to, is what yer lookin' for,....

Crud gums it up, restrictin' the fuel flow,...

Ya might be able to just clean out the 1 there now,...

Have ya run yer motor on a remote tank, to test whether yer tank has problems,..??

Does the fuel level in the tank, change the pattern of operation,..??
A cracked dip-tube can do funny things sometimes,... allows air into the fuel flow,...

 

[MikDee]

Re: anti siphon valve

If the barb is hollow, then either someone messed with it, or it fell apart, so check for the ball (BB) and spring.

 

[studders]

Re: anti siphon valve

Ayuh,.... Welcome Aboard,.... At the tank's outlet, the fittin' the hose attaches to, is what yer lookin' for,....

Crud gums it up, restrictin' the fuel flow,...

Ya might be able to just clean out the 1 there now,...

Have ya run yer motor on a remote tank, to test whether yer tank has problems,..??

Does the fuel level in the tank, change the pattern of operation,..??
A cracked dip-tube can do funny things sometimes,... allows air into the fuel flow,...

There was a little piece of debree in it when I looked through it. As for the fuel level I haven't noticed any changes in operation. I'm going to try and de-winterize it this weekend. The only barbs that I find online are also hollow that's why I started questioning it because some images on google show that it should have a spring, ball and sleeve in it. Also as for running on a remote tank I have no idea what you are talking about, lol

 

[fishrdan]

Re: anti siphon valve

This is what you're looking for Moeller Aluminum Anti-Siphon Valve. Looks like a normal hose barb until you look at the end of it, ball spring and retainer are hidden inside.

 

[NHGuy]

Re: anti siphon valve

All they do is keep fuel from coming out unless there's suction from your fuel pump. I took mine out when I got my boat and just ran some gas and carburetor cleaner through it while exercising the spring with a plastic stick.

 

[UncleWillie]

Re: anti siphon valve

... Also as for running on a remote tank I have no idea what you are talking about...

The idea is to run it on a portable 3-6 gallon plastic tank typically used for smaller Outboard motors.
That will eliminate any issues that may be associated with the built in fuel tank.
If you still have the same problem on the portable tank,
you will know that the problem has nothing to do with the boat fuel system up to that point.

 

[studders]

Re: anti siphon valve

This is what you're looking for Moeller Aluminum Anti-Siphon Valve. Looks like a normal hose barb until you look at the end of it, ball spring and retainer are hidden inside.

Is there such a size 3/8 1/2 npt. The 1/4 is too small and the 3/8 also looks like it to small. The thread on the one I have is bigger than the 3/8 hose barb.

 

[UncleWillie]

Re: anti siphon valve

The thread on even a 1/8 pipe is going to be bigger than the 3/8 barb.

Pipe is dimensioned from the Inside Diameter.
The ODs and the threads are way bigger than indicated.

1/8 Pipe = 0.405 OD
1/4 pipe = 0.540 OD
3/8 Pipe = 0.675 OD
1/2 pipe = 0.840 OD

 

[studders]

Re: anti siphon valve



Ayuh,.... Welcome Aboard,.... At the tank's outlet, the fittin' the hose attaches to, is what yer lookin' for,....

Crud gums it up, restrictin' the fuel flow,...

Ya might be able to just clean out the 1 there now,...

Have ya run yer motor on a remote tank, to test whether yer tank has problems,..??

Does the fuel level in the tank, change the pattern of operation,..??
A cracked dip-tube can do funny things sometimes,... allows air into the fuel flow,...

I know this is a 4 year old post but I’m still having issues with this and now is getting worse. Even at half throttle. Do you have a part number for the dip-tube. I’m going to take it out and clean it today but was just looking for a part number in case I need to get one.

 

[Bondo]

Do you have a part number for the dip-tube.

Nope, depends on who built the tank,....

I've always build my own,... outa copper, or nylon tubin',,,,

 

[studders]

Good morning. Just touching base on this issue I’m still having. I don’t get out that much anymore on the boat is the reason I don’t give updates on here. Still bogging down at wot or even half throttle now. I have replaced the dip tube in the tank and changed the fuel filter. What could be next? I’m thinking either rebuild or replace the carb and or maybe the fuel pump is going bad. I don’t know what are anyone’s thoughts or what to look for next? Just seems like it’s gettimg to much fuel somewhere is maybe why it’s flooding and bogging down. Thanks for any input.

 

[Scott Danforth]

many times bogging is from too little fuel (plugged or non functioning accelerator pump circuit)

if you are getting too much fuel, many times its either a failed fuel pump and there will be fuel in the clear hose to the spark arrestor or your needle and seat is bad and your simply pouring fuel down the carb

 

[studders]

many times bogging is from too little fuel (plugged or non functioning accelerator pump circuit)

if you are getting too much fuel, many times its either a failed fuel pump and there will be fuel in the clear hose to the spark arrestor or your needle and seat is bad and your simply pouring fuel down the carb

Thanks. As soon as I can I’ll check that out. I wasn’t quite sure on which one it was lol. Either to much or not enough fuel. But that’s exactly what it is doing. I will be cruising and then all of a sudden it will start to bog and lose power. I have to then put it in neutral for a few seconds and let it idle down and then take off again.

 

[Scott Danforth]

if it smells like its running rich, its too much fuel.

could be tank vent too. check that as well.