Problem Valve at Fuel Tank Elbow

[itguy]

My 2120 apparently has a problem with the valve attached to the elbow that connects to the fuel tank (next to the sending unit). After first replacing the fuel hose bulb and then the filter, the folks at Parker think it must be the valve since neither of the above solved the problem of the bulb collapsing resulting in fuel starvation.

They also said I didn't have to worry about replacing it...I could just leave it out.

Has anyone had this valve fail, and did you leave it out or replace it? My Parker is a 2005 with a 200 HP Yamaha 4-stroke

Thanks.

Itguy

 

[Megabyte]

Yep. It is called an anti-siphon valve and many people just remove it.
Do a search here using anti-siphon valve as key words and you should fine lots of information about it.

 

[itguy]

Thanks, Megabyte. Hopefully all I need to do is replace/remove the AS Valve. Unfortunately, the other threads suggest there may be more to it than that.

 

[itguy]

Megabyte,

Some of the other threads you turned me on to suggest that the fuel tank side of the "elbow" that includes some sort of screen and tube may be clogged, etc. If this is the case, should I replace with a new assembly or will I be able to clean the existing one? I imagine it's not too expensive if my Parker dealer has one in stock.

Thanks.

Itguy

 

[Megabyte]

I'm not certain, as I've never had a problem with my anti-siphon valve. (hopefully I haven't just jinxed myself :shock: )
Hopefully someone who has had theirs apart can weigh in...

If the part isn't overly expensive, I'd be inclined to just replace it (and the gasket) with a new one.

 

[itguy]

This is what I have done so far, in order:

Replaced the bulb
Replaced the external fuel filter/seperator
Replaced the anti-siphon valve
Moved the fuel line to the second (unused) fuel port in the tank

Observations:

When I replaced the fuel line bulb, no change at all to the flow. When I replaced the fuel filter, no change to the flow. When I replaced the anti-siphon valve (it was really clogged - I don't know how any gas was getting through!), I was able to run at 5400 RPM's for 15 to 20 minutes. I figured it must have been fixed, so I decided to take a look at the fuel bulb and it was still compressed! When I slow to idle, the bulb refills after a few seconds (it used to take 2 or 3 minutes to refill before I replaced the anti-siphon valve). So I tried connecting the fuel line to the spare port in the tank thinking that, if the pick up tube inside the tank was clogged, maybe the second pickup tube was clean since there had been no demand on it. This did not make a difference.

Even though it never hiccuped one bit at 5400 RPM's for 20 minutes, I'm still nervous about having the bulb compressed.

Should I worry about this, or just wait and see what happens. It must be getting enough fuel, I'm just nervous about causing engine damage.

Thanks.

Itguy

 

[DaleH]

From what you wrote, it appears you still have not checked the fuel pickup as a source of the problem. But have you also checked the fuel vent? They can clog up from salt exposure, clean it with vinegar or fine wire. Try running the boat now 'as is', with the fuel cap OPEN, and if the bulb doesn't collapse, then the vent is your problem.

From an earlier post of mine, re: tanks:

"A/S valves = http://classicparker.com/phpBB2/viewtopic.php?t=292

To remove that 'boss' that your fuel line barbed fitting attaches to (that looks to be welded), use (2) box wrenches 180-degrees apart.

Check to see if there is a filter on the end of the fuel pickup. If you remove the a/s valve, then also remove any screen on the fuel pickup end ... relying on your Racor fuel/water filter for any contaminant removal.

I did confirm with Racor that it does take a few inches of Mercury of vacuum to 'pull' fuel through their filter element ... as suspected. They stated that 'if' your Racor is mounted in a plane HIGHER than the fuel tank, then if the fuel line was to rupture AFTER the fuel/water separator, then fuel would most likely not be drawn through the filter and continue to flow.

If, however, any point of your fuel line lies or routes BELOW the level of the top of your fuel tank, then I would keep the anti-siphon valve installed and if doing that, then make sure there is a filter screen on the fuel pickup to prevent crud and lint from clogging the a/s valve.

To me, on OB-powered rigs, it is best to always have the fuel delivery system running UPHILL, from tank to f/w separator and then out of the boat ... then any angle needed to route to the motor."

I will also say that OEM fuel primer bulbs can deteriorate in the sun and I have replaced mine on occasion. Try running your boat with the gas line hooked to another small tank. If your bulb doesn't collapse, then look to the tank pickup. If the bulb still collapses - replace it.

 

[itguy]

DaleH,

Thanks for the reply. I ran the boat with the fuel cap open and this did not help, so I assume the vent is okay. The replacement bulb I used was not the Yamaha bulb, but one made by "Seacrest"? or something like that. It did seem to be made of a softer rubber than the OEM bulb. Do you think that could make the difference?

Itguy

 

[Megabyte]

If the bulb still collapses - replace it.

But not with one of the 'generic' (Perko) items normally found at West Marine.
Get a genuine Yamaha replacement bulb. There is a difference. :wink:

 

[itguy]

Purchased a Moeller Marine straight through 3/8 to 3/8 connector to see if the problem was the anti-siphon valve. Ran beautifully at 5400 RPM with only the slightest bulb compression.

Decided to try the Moeller Marine 3/8 to 3/8 anti-siphon valve. The spring seemed softer than the anti-siphon valve the Parker dealer gave me - that one was for a Johnson/Evinrude, and it didn't work - collapsed the bulb (but he said they were all the same). Bull! The Moeller Marine anti-siphon valve worked perfectly - only the same amount of minor compression as with the straight through connector.

Decided to see if I could totally eliminate any bulb compression and purchased a Moeller Marine bulb. Voila! No bulb compression at all!

There is a difference in bulbs and valves. Thanks to all for your thoughts and recommendations.

Itguy