Fuel vent question

[maineiac5586]

1997 wellcraft 190ccf center console.
I was inspecting the fuel tank vent and have a question. 5/8 vent hose going to a thru hull vent. I have trouble filling the tank all the way. It goes from nothing to expulsion of fuel very quickly. I unscrewed the vent cap and looked in and saw the picture below. Does that look correct? If I need to replace it what is the best vent I can get? Thanks

 

[Bondo]

Ayuh,..... Never seen a fuel tank vent that looks like that,.....
All the ones I've seen are a cast 90* elbow through the hull,.....
The vent line, should go from the fitting, Up into a loop, 'n then drop into the tank, falling all the way,....

 

[maineiac5586]

Ayuh,..... Never seen a fuel tank vent that looks like that,.....
All the ones I've seen are a cast 90* elbow through the hull,.....
The vent line, should go from the fitting, Up into a loop, 'n then drop into the tank, falling all the way,....

The vent line is fine just concerned with the vent itself

 

[MikeSchinlaub]

I agree with Bondo. That doesn't look like a proper fuel vent. A fuel vent should be as he described, an elbow with the opening facing down and a fine screen in the hole.

That looks like some kind of one way valve intake or output. If that's what your vent line is hooked up to, it's likely the problem.

 

[dingbat]

Blow compressed air back through the vent. Quite possible the vent is water logged

Run into several boats over the years that were slow to fill because of the orientation of the fill and vent.

Boat would take fuel w/o incidence on the trailer, yet kept kicking out on the water

 

[Scott Danforth]

vents are supposed to have a vertical loop in them to make a "P" trap

or they are to be the integral P trap style.

see figure 4 in the fuel system section in the link

https://www.uscgboating.org/assets/1/AssetManager/FUELSYSTEM1.pdf

 

[MikeSchinlaub]

vents are supposed to have a vertical loop in them to make a "P" trap

I've never actually seen one do this, whether it's an older boat with a seperate vent or a newer one with a vented cap.

 

[maineiac5586]

I'm mostly concerned with the appearance of the valve inside the hole. What's up with the little hole? Is that supposed to be like that?

 

[MikeSchinlaub]

This is what your fuel vent should look like. There shouldn't be any valves in it. There are other styles, and newer gas fills have the vent as part of them.

 

[Chris1956]

Gee, your fuel tank looks to be made of fiberglass. If so, the alcohol in today's gasoline can dissolve some of it's components possibly causing leaks.

I agree that the tank vent looks unusual.

As for your filling issues. You normally want the vent fitting on the tank to be as far forward as possible. That allows the minimal amount of splash of fuel out the vent.

 

[MikeSchinlaub]

Gee, your fuel tank looks to be made of fiberglass. If so, the alcohol in today's gasoline can dissolve some of it's components possibly causing leaks.

It could be plastic glassed to the boat. I saw one like that once. I think it was the Skeeter I did the floor and stringers in.

 

[maineiac5586]

Turns out that little black speck in my vent tube was a tiny piece of plastic. I removed the vent and will be installing a flush mount vent with elbow along with new filler hose. New vent hose and new fuel feed hose. Crazy how expensive hose is these days but will give good piece of mind. Thanks for all the help.