Fuel pumps do not shut off when tank full.

[MCNPathfinder]

Re: Fuel pumps do not shut off when tank full.

Oh to be able to afford to fill my boat up all the way... Mine does the same thing.

 

[JoLin]

Re: Fuel pumps do not shut off when tank full.

All fair if you have a large fuel tank, but guys with smaller tanks will understandably try to top them off. As far as expansion; the tank is vented. If you fill it up to the very brim and then let it sit in the heat or such so that it expands and runs out the vent, you're a little crazy... But most fill it up and then go use it.

An example, my last boat (15' trihull, 80hp merc) had a 12 gallon fuel tank. Not a removable topside tank - a permanantly fixed tank with a thru hull fill and vent. The fill hose was around a foot long, roughly. 12 gallons can go pretty quick on an inefficient old 2 stroke, so I would try to get it as close to full as possible. Sometimes, I misjudged or spaced a little and sent a few ounces out the vent.

Keep in mind that most small boats are not filled up on the water - they're filled at gas stations. So that spilled gasoline ends up on the concrete or pavement, and evaporates. I'm not saying go pump full-bore and spill fuel everywhere with reckless abandon, but lets not get all emotional about a little spillage either, these incidents arent the exxon-valdez.

Yeah, you're right- I didn't think that all the way through... I apologize to all the 20-gallon tank guys. It just frosts my nuts when I see spillage at the fuel dock, right into the water.

 

[UncleWillie]

Re: Fuel pumps do not shut off when tank full.

Most boats, however, are like portable fuel containers - you must pump with caution.
...

There is no reason that the pump should not shut off automatically when filling a portable container.
The pump nozzle has a hole about an inch back from the end.
This hole has suction on it.
If liquid fuel enters the hole, the pump shuts off.

If the hole is not down the pipe it can not detect the overflow.
Do you pump with the nozzle fully "Down the Throat" of the boat or just the tip of the nozzle?

Some Boats have the vent line completely separate from the fill port and others have the vent just under the cap.
If the spewing is coming from the VENT Line, the overflow will not be detected.

 

[mnypitboat]

Re: Fuel pumps do not shut off when tank full.

Exactly. You're supposed to know how much fuel you need. Why would you try to fill the tank and fill hose to the brim? Not only are you hauling extra weight around, but you aren't leaving room for expansion. Tank should be no more than 90% filled. Spewing fuel into the water is just another of those things that make boaters an easy target for eco-regulation... and I use that water too, you know.

NONE of the boaters I know tell the guy at the fuel dock to 'fill 'er up.' We tell him how many gallons we're putting in. He watches the pump.

My .02

I fill up at a gas station on the trailer, not on the water. That being said, How do you know how much fuel you used if you dont fill it up. I would prefer to keep it below the filler tube, but how do I know? It took 45 gallons to go where we went last weekend. I had no idea how much until I filled it, then I was able to get gas money from all the riders. We had a strong headwind, and against the current the whole way there, and used about double the amount of gas than on the way back.

Then there was the other day when we had taken the boat out 3 times, tubing, skiing, etc each time. We got to the marina where we dry store the boat, and it was obvious someone had siphoned some gas out of the boat. Well, it took all of 15 gallons. I expected it to take a minimum of 30.

Gas guages are less than accurate on boats, so I ask again, how do I know how much gas I need??

 

[Grandad]

Re: Fuel pumps do not shut off when tank full.

I have the problem of gasoline escaping at the vent at the same instant that the auto-shutoff activates. It squirts a few tablespoons, but I'd sure prefer not to pollute. It's only a 15 gallon (US) tank which is on the small side for an I/O, and it's above the floor, so the filler pipe is max 18" long. With the separate vent mounted 2" below the deck in the hull, that reduces the height above full to 16". The whistle in the vent line sounds like a good idea, but I wonder if the filler neck would need to be reduced down closer to the standard nozzle size so the air only vents through the whistle, not the neck, like BoatDrinks says.
Or would this make things worse, adding the nozzle pressure to the gas discharge at the vent?
Has anyone cured this problem using the vent whistle? - Grandad

 

[spdracr39]

Re: Fuel pumps do not shut off when tank full.

The fuel backs up the vent line at the same time and level it backs up the fill hose so if it stops whistling its coming up the tubes. No the line would not because the fuel going in prevents the air going out that's why you have the vent in the first place. I'm guessing that your fill hose is too short for this vent whistle to be effective but not sure.

 

[UncleWillie]

Re: Fuel pumps do not shut off when tank full.

I would think the vent would whistle the whole time you were filling the tank.
As the fuel goes in the air must come out!

If you lengthened the vent line so it was routed above the fuel fill before it attached to the hull through, the fuel fill would overflow first and the fuel level would never get high enough to make it out the vent.

Also any water splashing in the vent would have to go uphill first before it could make it to the tank.
Essentially a reverse "P" trap like under the sink.

 

[mnypitboat]

Re: Fuel pumps do not shut off when tank full.

Yeah, mine doesnt come out the vent first. It comes out the fill first then gurgles a little out the vent. But it has to come out the fill a lot to do that. WIth listening close, I have gotten it down to just enough to annoy me. Last time it had evaporated faster than I could clean it. I keep 409 in the rear of the boat in the wash down basin, and those blue towels they sell at the auto parts store. I clean it regardless of whether there is still fuel on the gelcoat or not.

So since it looks like it is a normal thing, I suppose I will keep doing it this way.

 

[JoLin]

Re: Fuel pumps do not shut off when tank full.

Gas guages are less than accurate on boats, so I ask again, how do I know how much gas I need??

IMO, they're close enough that after several times out you should have a pretty good idea of how much error is built into yours. I know how big my tank is, and I know by now that my gauge reads approximately 1/8 lower than the actual level of fuel in the tank. I don't know a better way to explain it.

 

[mnypitboat]

Re: Fuel pumps do not shut off when tank full.

IMO, they're close enough that after several times out you should have a pretty good idea of how much error is built into yours. I know how big my tank is, and I know by now that my gauge reads approximately 1/8 lower than the actual level of fuel in the tank. I don't know a better way to explain it.

I think I will stick to my method til something else comes up that is better. I only asked because I thought it was a problem, but since it seems to be the norm, rather than the exception, I will stick to the rag, 409 and water method.

 

[tincanman]

Re: Fuel pumps do not shut off when tank full.

yup, happened to me also. I Just filled my new to me starcraft up for the first time. About 5 gallons in, I heard the air gurgle, pump didn't shut off, and this thing spit fuel all over me and the splashwell for a few seconds. I was soaked. the inside of my truck smelled like fuel for over a week from me climbing back in after my bath. I can only fill at about half speed or I get the bath. It takes a long time to put 35 gallons in at that pace. I have never had a boat that did that to me before. That whistle may be the ticket.

 

[Philster]

Re: Fuel pumps do not shut off when tank full.

My current boat is the first one I can pump up like a car. Set it and forget it. Vent is at gas cap, more along the lines of an automobile setup.

Separate vents can fill up and overfill with gas and leave the pump with no clue as to what is going on.

 

[haulnazz15]

Re: Fuel pumps do not shut off when tank full.

I've never owned a boat/jet ski that would automatically shut the pump off, so I guess I'm used to it. I never saw it as a problem. You can hear the change in sound as the tank gets near-full most of the time and when the fuel gets into the filler neck. Of course I also don't think much about it when the 1/4 cup of fuel has dripped into the water.