Odd fuel vent hose issue

[tupperj]

Greetings all!
Strange problem with an 86 SeaRay Seville. Filled the tank and then took the family for a run on the lake, about 20-30 minutes. Lost power and limped back to the dock at 2500 rpm.
Popped the doghouse and began checking the obvious issues. Noticed that the fuel tank vent hose was dripping fuel. Seemed to be wet up to about the level of the carb. Gave up working on things until I got the boat home at that point.

This makes no sense to me. I can't think of a reason for there being liquid fuel that far up in the tank vent hose. I did notice the hose is cracking, and will be replaced, along with the fill hose as a preventative measure. Fuel line is already new.

Anybody experienced this? What am I missing that would cause fuel to be leaking from the vent hose that high up? The hose was wet about a foot above the tank level.

Thanks all!

Paul

 

[Chris1956]

Re: Odd fuel vent hose issue

Paul, Gasoline will slosh around, and even spit out the vent hose if the tank is full. Replace the hose.

If you haven't figured out your engine issue, you might repost in the I/O section(provided it is an I/O). You might check the antisiphon valve in the neck of the fuel pickup. On my '88 SR, you needed to unscrew the fuel pickup tube from the elbow to get to the A-S valve.

 

[tupperj]

Re: Odd fuel vent hose issue

Chris,

Thanks for the response, the hose will be replaced before the boat goes anywhere else.

Just seemed strange that there was THAT much fuel so high on the hose. At least a new hose will contain things properly.

Do you know if the fitting on the transom is just a straight fitting, or is there some sort of valve in there? I probably should know that, but sometimes it sucks to get old!

As for the engine issue, as soon as I can get out in the heat and do a compression test, I'll be posting in the Merc I/O section. Pretty sure I blew a head gasket due to an overheat from a bad impeller. Totally my fault, and I wear the cone of shame.

Thanks again, and take care!
Paul

 

[Home Cookin']

Re: Odd fuel vent hose issue

I'm not sure how the vent hose could drip fuel; seems the fuel might rise inside it, but it should be sealed from tank to overflow. How did the fuel get outside the hose?
Are you sure you're not getting sea water in the vent?
If it's raw gasoline you have a serious hazard going on.

The vent out the transom has to have a swan neck fitting to keep water out. Personally, i think transom vents are a design defect. I had a through-hull that cost me an engine. So while you're at it, put in a vented fill cap and delete the through-hull.

 

[Andy'sDelight]

Re: Odd fuel vent hose issue

Do you "top off" the fuel when filling her up? If so, stop doing so. Gasoline expands in the tank during warmer days. It tries to find someplace to release, your vents being the easiest and logical place.

 

[seabob4]

Re: Odd fuel vent hose issue

Did you actually check the conditions of your hose clamps at the vent neck on the tank? Tour fuel is coming from the neck, not the hullside vent fitting...

 

[sasto]

Re: Odd fuel vent hose issue

Did you actually check the conditions of your hose clamps at the vent neck on the tank? Tour fuel is coming from the neck, not the hullside vent fitting...

......new hose, new ss clamps, sounds like a done deal to me.

 

[tupperj]

Re: Odd fuel vent hose issue

I'm not sure how the vent hose could drip fuel; seems the fuel might rise inside it, but it should be sealed from tank to overflow. How did the fuel get outside the hose?
Are you sure you're not getting sea water in the vent?
If it's raw gasoline you have a serious hazard going on.

The vent out the transom has to have a swan neck fitting to keep water out. Personally, i think transom vents are a design defect. I had a through-hull that cost me an engine. So while you're at it, put in a vented fill cap and delete the through-hull.

Home Cookin,
The vent hose is cracking and in need of replacement. What baffles me is that it was wet at a level a good foot above the level of the tank. Definitely gas, not water. Agree on the hazard, that's why the boat got put back on the trailer and hauled home.

Not sure a vented fuel cap would be any better, as my fuel fill is also on the transom. Would you still recommend the change?

Thanks for the input!
Paul

 

[tupperj]

Re: Odd fuel vent hose issue

Do you "top off" the fuel when filling her up? If so, stop doing so. Gasoline expands in the tank during warmer days. It tries to find someplace to release, your vents being the easiest and logical place.

Andy,

Agree with you. The marina filled the tank, and we ran a good 30 minutes at close to WOT before things went south and we limped back to the dock. Would have thought I would have burned off enough fuel to avoid the expansion issue, but perhaps not.
Will heed your advice in future.

Thanks!
Paul

 

[tupperj]

Re: Odd fuel vent hose issue

Did you actually check the conditions of your hose clamps at the vent neck on the tank? Tour fuel is coming from the neck, not the hullside vent fitting...

Seabob,

The hose needs replacing, a close exam shows cracking of the rubber. I don't think the leak is coming from the fitting though, as the hose was wet to a level a good foot above the tank.

Agree with other posters that removal/replacement should take care of the leak, just baffled as to how liquid fuel could get that high above the tank after burning some out of the tank.

Ah well, just another mystery of boat ownership. Will definitely get new hoses in there, and new clamps. And I'll make sure someone with a working nose is with me to sniff for fumes. Violent contact with a softball years ago left me without much of a sense of smell. A blessing sometimes when the kids were in diapers, but problematic other times.

Thanks for your insight!
Paul