Fuel system issues

[Tipsy]

Recently purchased my first pontoon. It's a Sun Chaser 23', Has a Suzuki 115. Runs just fine, starts right away no troubles.
Permanent tank in back under sundeck. I filled it at the local gas station with non-ethanol gas before our first time out. Filling was a little slow going but I figured it was just because the fill was up high where I had difficulty getting the nozzle into the fill. Fast forward to a month later and I stop at the marina for my first fill-up there. The pump there kept shutting off and so I only got a small amount of gas. The dock guy said he could see the gas sitting in the filler line as if it was full.
I have checked everything.
The vent is clear.
The vent line is clear.
The vent check valve in tank is operating fine.
The vent carbon filter is clear with no restriction.
The filler door is fine.
The 1-1/2" filler hose is clear and straight down at an angle so no dips in it.
The filler check valve is clean and clear and operates great with no resistance at all.
When I removed the vent check valve from the tank I looked into the tank and all was clean.
Anyone have any ideas what else I can check? My next step is stopping at the marina again and see if it happens again.
Could it have been some sort of vapor lock fluke?
Thanks to all of you. I've been away for some time but I'm back now.
Jeff

 

[airshot]

Siphon some fuel from the bottom of the tank and check for water. Water in fuel is a popular problem. Many fuel stations don't keep up with the proper maintenence, so getting contaminants right from the start often happens.
I have saw where water comes in thru the vent line.....be sure the vent hose has in upward loop so any spray can't run back into the tank. Try taking a small sample of fuel when your filling your tank, test that for water or other contaminates. Do you have an inline water seperator/ filter....if not, time to install one.

 

[Scott Danforth]

Problems filling are either an obstruction in the fill line, or a blockage in the vent line

 

[Jeff J]

Checking the vent would be good. Was the vent check valve working when you pulled it?

It may also be that you had just the right angle when you to stretched to fill. Experiment with the depth and angle of the fill nozzle. My boat has been very picky about taking fuel since it was new. Modern pumps all seem to be either on or off. Trickling is no longer an option but I don’t have to if I can hit that magic angle. I have driven some road vehicles that required the nozzle be held at an odd angle to fill too. Generally speaking, flow has to be directed away from the vent. On my boat that means the nozzle is held inverted and not all the way in.

 

[jlh3rd]

could just be a "learning" process.
Gassed up my '06 pontoon last friday and you'd think I'd never gassed or owned a boat before.

 

[airshot]

Sorry did not catch the " filling" issue with your fuel system. Not unusual with boats and built in tanks. Often the main fill hose goes in awkward positions making filling difficult. The gas nozzles push fuel faster than the air can escape. My own fuel tank has that issue. It needs to be held at a slow filling speed or the trapped air creates pressure and overflows the fill neck. I have saw cases where two vent lines were used to help air escape, one vent line close to the tank where the fill hose attaches and another vent line further up closer to the fill cap. Some claim this helps alot......

 

[dingbat]

Make sure your vent line is clear.

Seen water accumulated at the “dip” in the line a number of times. A bit of compressed air clears it

 

[Tipsy]

Here’s a picture of the setup.

 

[airshot]

Doesn't look like much angle on that main fill hose.....

 

[DeepCMark58A]

Try a gas can see if it goes better.

 

[Tipsy]

Doesn't look like much angle on that main fill hose.....

Ya it doesn’t look like much but it’s deceiving. It’s got enough angle. Can’t go any higher even if I wanted.

 

[Tipsy]

Try a gas can see if it goes better.

I’m planning on trying that.

 

[Chris1956]

Take out the one-way valve in the filler tube and see if it works better.

 

[Tipsy]

Try a gas can see if it goes better.

So, I tried about 4 gallons of gas from my 5 gallon can and it went in just as smooth as can be. Later yesterday we went out on the lake and when we were at a marina we tried getting gas and again had the same trouble. I talked with the guy filling it and suggested slower and holding the nozzle upside down and that seemed to help. He laughed and said, "you'd be surprised how many boats I have to have the nozzle held upside down".

 

[Tipsy]

Take out the one-way valve in the filler tube and see if it works better.

I like this idea. I may try it. There's just not much else I can think of. Bypassing the charcoal canister is my other option. It allowed air through it just fine when I checked it, but I'm not sure if maybe it's just not clear enough for the actual pressure from a gas pump nozzle. That fuel filler line is expensive stuff, maybe I'll just flip the valve over, so it hangs open instead of closed.

 

[Chris1956]

Gee, a piece of copper or PVC plumbing pipe can easily substitute for the one way valve, for testing purposes.

If that doesn't fix it, temporarily disconnect the charcoal canister inlet to take that out of the equation. Is the fuel tank vent clear?

 

[DeepCMark58A]

So, I tried about 4 gallons of gas from my 5 gallon can and it went in just as smooth as can be. Later yesterday we went out on the lake and when we were at a marina we tried getting gas and again had the same trouble. I talked with the guy filling it and suggested slower and holding the nozzle upside down and that seemed to help. He laughed and said, "you'd be surprised how many boats I have to have the nozzle held upside down".

I had a 1968 International Scout that SOB hated getting gas put in it from a gas pump, wasn't a dailey driver so I just gas canned it to fuel it.

 

[Jeff J]

The charcoal canister may be worth a look too. I expect wet charcoal could restrict airflow.

We had one if those charcoal canisters fill with water. It took me a minute to figure out where the water in the fuel was coming from. The fuel vent could get submerged on a tight left turn and there was no way to get a high spot in the vent hose so water would drain back overboard.

 

[Tipsy]

Gee, a piece of copper or PVC plumbing pipe can easily substitute for the one way valve, for testing purposes.

If that doesn't fix it, temporarily disconnect the charcoal canister inlet to take that out of the equation. Is the fuel tank vent clear?

1-1/2" ID hose needs an odd size piece of pipe. That's why I figured, even though the one way valve is operating great I would just roll it over to have it lay open. We shall see.
Fuel tank vent is clear. Vent lines are clear. Canister allows air to easily pass through, so I'm guessing clear but will disconnect it next time to test if that's the problem.

 

[Tipsy]

The charcoal canister may be worth a look too. I expect wet charcoal could restrict airflow.

We had one if those charcoal canisters fill with water. It took me a minute to figure out where the water in the fuel was coming from. The fuel vent could get submerged on a tight left turn and there was no way to get a high spot in the vent hose so water would drain back overboard.

I have no problems with water in fuel, engine runs fine. Vent is up plenty high so submersion or water intrusion is very unlikely. Vent is a "P-trap" style to help with that as well. Air flows fine when I blow through canister, but maybe my air pressure is less than incoming gas from the pump would create. So I'll test that.