Anti Syphon fuel valve

[captglm]

My primer bulb is being sucked in. I checked the line to the tank, it was clear.. I was told it could be my anti syphon check valve located where fuel comes out of the fuel tank pick-up. can I just put a 3/8 fuel barb there instead of the check valve?

GM ><>

[patchesII]

oftentimes the check valve is inside the elbow coming out of the tank. alot of them are threaded 3/8 npt(at least mine was) so you'll just need to find an elbow that fits. also check your vent on your tank to make sure it's clear
if you haven't already you may also replace your bulb with a quality replacement. stay away from the cheap ones you get at walmart

[j_martin]

oftentimes the check valve is inside the elbow coming out of the tank. alot of them are threaded 3/8 npt(at least mine was) so you'll just need to find an elbow that fits. also check your vent on your tank to make sure it's clear

Mud daubers love to build a winter nest there.

[captglm]

I took the anti syphon valve off at the pick up.. I took the fuel line off at the bulb and blew through the line from the tank, its open. I also lightly blew into the tank, its open.. I bought a new Mercury bulb, its working.. I will replace the Anti Syphon valve tomorrow... I would rather put a 3/8 hose barb on be done with it but I was told its coast guard regulations to have the anti syphon valve on to keep fuel from getting into the bilge if a hose breaks or gets cut. not sure about the vent--- I have a 2004 Nitro bass boat. I don't see a fuel vent anywhere on the boat. where is it located? could it be in the fuel cap?

GM ><>

[Lockjaw]

I put a hose barb on mine, got it at Lowe's. I kept getting a check engine light on my Johnny and an alarm at WOT. Sometimes at less then WOT.

Where is your tank? CG would have fun trying to get to mine to check it. :thumbsup:

[captglm]

The fuel tank is under the seat . It has the fuel pick-up 3/8 line located in the top center of the tank that goes to the bulb and motor. I can also see another line (looks like about 3/4 inch) coming out the top of the tank on the far end running toward the cap and filler hose. I can't see where it goes, its to far under the fiberglass area. like you said the coast guard would have to take the middle seat out to even see the barb fuel pick up. I'm still a little concerned about the fuel issue if a hose breaks. those guys don't make regulations unless there's a reason but I also understand they have problems with the anti syphon valves sticking and causing fuel restrictions. One of those Dam if you do, Dam if you don't deals! Thanks for the advice.

GM ><>

[j_martin]

The fuel tank is under the seat . It has the fuel pick-up 3/8 line located in the top center of the tank that goes to the bulb and motor. I can also see another line (looks like about 3/4 inch) coming out the top of the tank on the far end running toward the cap and filler hose. I can't see where it goes, its to far under the fiberglass area. like you said the coast guard would have to take the middle seat out to even see the barb fuel pick up. I'm still a little concerned about the fuel issue if a hose breaks. those guys don't make regulations unless there's a reason but I also understand they have problems with the anti syphon valves sticking and causing fuel restrictions. One of those Dam if you do, Dam if you don't deals! Thanks for the advice.

GM ><>

The filler is 1 1/2 inches. The 3/4 inch hose is the vent. It usually goes to a chrome fitting on one side of the boat, near the back probably. It could be built into the filler fitting. It's usually guarded so spray hitting it when yer under way won't go directly into it. Sometimes there's an overflow preventer in the vent line. I have one on my bass boat to keep it from spilling fuel out the vent.

If you can blow into the tank, either at the filler or at the fuel line, and it doesn't blow back, the vent is not plugged.

If any part of your fuel line is below the top fill level of the tank, the anti-siphon valve is needed. So if your fuel line is in the floor, it's needed. If it goes immediately up the side and runs along the gunwale, the anti-siphon valve would not be needed. It's to keep yer fuel tank from dumping into the bilge if something breaks.

hope it helps
John

[staylor]

....from the last time I checked the regs is that its required only if a portion of the fuel line is located below the tank fitting. If you rig so that the line from the tank to the motor stays above the top of the tank then the valve is not required. This is usually pretty easy to do. Since the boat builder cannot be sure of the riggers capability, most of them put the valve on as a standard procedure. For example, on my current rig there was a loose section of fuel line that drooped below the tank top- about a 6 inch length, but in the event of a leak/break in the hose it could have started to siphon gas into the bilge from the tank. I added a few tie wraps to elevate this one section of hose and then had no issues with removing the valve. Most well rigged boats have all wires and hoses tie wrapped together every 6-8 inches so as long as the fuel line is above the tank and the tie wraps are inspected now and then there will be no problems from running without the valve.
Doug

[captglm]

Thanks everyone

My vent is located in the perko filler cap and hose fittings. If you take the cap off and look inside there's a small vent. I don't understand how it works with the cap on but its fine--anyway-- I put a $2.29 brass 3/8 hose barb fitting from Lowes on this morning and some Teflon tape, hooked up the ears and it solved the problem. Oh, the fuel hose is tied up above the tank!

My ball is hard again and flowing good.

Thanks
GM ><>

[Jeff_G]

Remove the barb and pull the teflon tape off. Fuel can degrade it and cause you problems down the line. Better to put a hydraulic sealant like Loctite has. Teflon tape is for plumbers not boats.

[captglm]

Will Do.

Thanks
GM

[yachter55]

I thought the anti siphen valve was so all the gas in the line will not drain back into the tank. I put a Earls valve in mine .

[Jeff_G]

No it's for when a line breaks it doesn't fill the bilge with fuel. They are a constant source of problems and no outboards should run with one, just another restriction in the line ready to eat your engine. As long as your fuel line is above the tank to the engine you are OK to remove it. If the line isn't, move it and take out the valve.
Inboard boats are required to have it.

[Lockjaw]

When I looked at mine, I couldn't figure out how the engine could get enough fuel through it to run properly anyway.

Chuck it and go on. At least once its gone, you know it will never be the problem again.

:thumbsup::thumbsup:

[mackeral5]

another thing to check.....many fuel pickups have a screen on or in them. the only problem is that removing the fuel pickup from old tanks requires extreme care or you can have one hell of a mess with broke fittings, etc....