It's NOT the vent

Beefer · Nov 25, 2011

Past two times putting gas in, I've had to stop because the fill neck was filling with fuel. I'd have to stop and let it settle and go down. I figured some wasps or mud daubers got into the vent, so no big deal. It's an 80 gal tank, and I keep it at less then half full. For convenience and savings, I get my non-ethanol gas in 5 gal cans from a gas station nearby ($3.59/gal, about 1 mile away, vs. $4.29 and 2 miles out of the way to the marina). I've been doing this for over a year, and since it's not from a pressurized pump, I doubt I'm pouring too fast.

Anyway, finally got around to checking out the vent today. Disconnected it, blew into it while my hand was over the fuel fill, and there was free flow. Checked the screen on the vent, it was clear as well. I then put in 10 gals, and it still was backing up.

Any other ideas? I'm sure I'm missing something simple.

smokeonthewater · Nov 25, 2011

Re: It's NOT the vent

yep the fill hose may be crushed or kinked... there may be a blockage in it.... it may have a long run without enough drop

scoutabout · Nov 26, 2011

Re: It's NOT the vent

ya - that doesn't sound right. Can you get easy access to the fill pipe to make sure it hasn't been flattened somehow like smoke suggests? Perhaps you can also find something long and flexible to snake down there, assuming no tight-radius bends just to see if you run into something. On my boat I have to fill slowly as the vent can't seem to keep up but it's been like that since I've owned it. Your condition sounds new.

26aftcab454 · Nov 26, 2011

Re: It's NOT the vent

my boat is difficult to fuel also-takes way too long- I can see gas fumes escaping from the vent.
I flip the gas nozzel upside down and incerted as little as possible. I can only squeeze the lever 2-3 seconds at a time.
I'm gonna check it out.

etracer68 · Nov 26, 2011

Re: It's NOT the vent

I had to replace the wood under my 12gal tank this spring, so I figured I might as well go ahead and replace all the fuel lines. I never had any problems fueling up, and my fill hose is at least 2" dia, and makes 2 almost 90 deg bends. Both old and new hoses have a wire molded inside so they cant kink. I think the vent hose was 3/8 id. I put a small piece of brass screen in the vent so no critters can make any nests. When I do fuel up at a gas pump, I dont pull nossle all the way, just maybe half, so it can vent through the main fill hose too. I would say there has to be some kind of blockage somewhere. It only takes me a few minuts to put 10gals in.

Scott Danforth · Nov 26, 2011

Re: It's NOT the vent

since the USCG approved fuel hose has reinforcing wires, I doubt it is crushed. however if the fuel hose is degrading, the inside may separate and cause a blockage. I would guess that there is something in the fill hose as a blockage. Pull the hose and check for blockage. you should be able to put 80 gallons in as fast as the pump can supply it.

Jeep Man · Nov 26, 2011

Re: It's NOT the vent

Do you have any friends in the plumbing business? Some drain inspection cameras are as small as 1/2". If you can get your hands on one, run it down your filler tube and take a look.

Beefer · Nov 26, 2011

Re: It's NOT the vent

Scott Danforth said:
you should be able to put 80 gallons in as fast as the pump can supply it.

Yup, that's what I figured as well.

The fill hose is wire reinforced, and is embedded in flotation foam under the deck, and only has to make one 90 deg bend, but it's a gradual bend.

I think I have a snake (or something that will work as one), and see if there is something in there, but I couldn't imagine what. As for the hose deteriorating, it's possible, but I have never used ethanol fuel in the boat, which I would think would be the cause of deterioration of the line.

TMALEGA · Nov 26, 2011

Re: It's NOT the vent

You said it is under the foam. Is it at all possible the foam has crushed the hose enough and the wire inside it is restricting the flow also? I am not sure that is a real possibility or not but it sure sounds like a reasonable idea to check out also.

skyking897 · Nov 26, 2011

Re: It's NOT the vent

Had a somewhat similar problem with the fresh water tank on an RV. Took forever to fill with 40 gallons of water. I could blow thru the vent line like your situation but what was happening, was water would back up the vent which had a low hanging spot and the water would stay there restricting the exhausting air. While driving around, the sloshing water would back up the vent and lay in the low spot of the vent line causing a blockage. I ended up re-routing the vent line and problem solved. Your problem could be as simple as this or a restricted fill line.

Woodnaut · Nov 27, 2011

Re: It's NOT the vent

Here's a different possible scenario for you to consider. I hope I can explain it correctly.

Let's say for example, that the vent line line to your tank is on the aft edge of the tank. Let's also say that during fueling, that the vessel is high at the bow. Depending upon the geometry of the tank the vent line might be partially covered which could cause venting problems.

You could turn this scenario around with the vent line at the front and a "bow low" situation during fueling which might also cause problems.

Just a thought.

Beefer · Nov 27, 2011

Re: It's NOT the vent

Good thoughts, but the vent line is in the front, and the boat sits bow-high on the lift. This also occurs when filling when on the water (level).

smokeonthewater · Nov 27, 2011

Re: It's NOT the vent

danzaqk said:
This problem is a bit difficult

Eh not really, when we get a sewer pipe that wont drain we have no trouble.... Everyone knows to run a snake down the drain.... since it's a fuel hose we get stumped..... Problem is REALLY simple... trace the path the fuel takes and find the restriction.... It only becomes difficult when we try to solve the problem from the comfort of a computer chair. Put hands on the problem and take stuff apart.... It will be quite simple but maybe a bit of work.

EDIT: BTW no offense beefer.... I too have looked at something simple dragging my feet and not wanting to just dig in.... sometimes for a long time before I finally just get with it.

GA_Boater · Nov 27, 2011

Re: It's NOT the vent

Given your checkered deck post (What were they thinking?), is it possible something under the deck has collapsed. Put enough weight on the hose, wire won't help. You mentioned that only non-E fuel has been used. You know that fuel lines went bad before the introduction of ethanol. They just decay faster now. As smoke said, no offense meant, but sometimes we all try to avoid the inevitable. Hope it's an easy fix.

Beefer · Nov 27, 2011

Re: It's NOT the vent

I'm sure it will be an easy fix, once I get around to it. The deck above and around the filler hose is fine, it was just the coffin cover that was trashed. I have no real reason to suspect a structural failure.

Yeah, I've sort of been putting off snaking, but only because I don't have a snake, and don't plan on using the boat for a couple of weeks or so, so no need to fill (yet). I just have to find a snake-substitute (have no need for one to buy), I was thinking of using a measuring tape.

GA_Boater · Nov 27, 2011

Re: It's NOT the vent

Beefer said:
I just have to find a snake-substitute (have no need for one to buy), I was thinking of using a measuring tape.

A tape measure might not be stiff enough, but it may work. If it hit a block you will know how far down to start digging. Do you happen to have any heavy house wire. Like plastic coated 3 conductor. I have used that when I put my snake in a safe place. It was so safe I ended up getting an new one. :redface::facepalm:

rivermouse · Nov 27, 2011

Re: It's NOT the vent

I dont know what kind of snake youins are talking about. If the snake is made of metal and it starts grinding on something inside the line or tank etc and the entire area is saturated with gasoline and fumes...well.......??????I would use some heavy weed eater line.

smokeonthewater · Nov 28, 2011

Re: It's NOT the vent

Well you wouldn't used a power snake and no worries about sparks doing it by hand..... I guess you wouldn't want to be ramming it with a lot of force.

weedwacker line is nowhere stiff enough though.

RogersJetboat454 · Nov 28, 2011

Re: It's NOT the vent

rivermouse said:
I dont know what kind of snake youins are talking about. If the snake is made of metal and it starts grinding on something inside the line or tank etc and the entire area is saturated with gasoline and fumes...well.......??????I would use some heavy weed eater line.

Most likely not enough air (all liquid/fumes) in those areas to make anything happen. Now if he were to look down the filler neck while using a cigarette lighter for light.... that would be a problem.....

oregoncruiser · Dec 1, 2011

Re: It's NOT the vent

I had a similar problem occur when fueling from a 5 gallon can. What was happening was when I would insert the spout, the fuel would flow equally to both the fill line and vent line. After a minute or two it was vapor locked.

I ended up running a siphon hose down the fill hose side in order to allow the tank to vent. Then I used compressed air to blow out the vent line. Then when I went back to fueling from the can, I carefully routed the flexible fill spout to the left, down into the fill hose a couple inches.

In my case is was operator error, and was easily solved by trying to be smarter than my boat. (Yeah I felt stupid)

I would suggest you take a flashlight and look down into the fill location and see if this is your problem as well.

It's NOT the vent

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