Pumping fuel a gas pump

SALARGO

Cadet
Joined
Aug 8, 2010
Messages
7
Hi All,

I have a problem at the pump, I kept getting gas pump back as it was full, some had told me I may have venting problem but how do I fix that. Is there any part I have to replace? Help...
 

flycaster

Petty Officer 2nd Class
Joined
Aug 5, 2008
Messages
186
Re: Pumping fuel a gas pump

You will have to get to the top of your tank and locate the vent line.
There should be two hoses (lines) going into the top of the tank.
Follow each line to see where it goes to. Also check to see if there are any kinks in the lines.
A kink in the fuel input line could cause a back flow as well as a kink in the vent will also cause a back flow.
You do not indicate what model or age of your boat. There may be a problem with the ethanol gas attacking the gas lines, if an older boat.
 

SALARGO

Cadet
Joined
Aug 8, 2010
Messages
7
Re: Pumping fuel at gas pump

Re: Pumping fuel at gas pump

I have a 2001 key largo model 172, it was using only ethenol gas, it that is true what is my fix. Thanks.
 

Peter Eikenberry

Chief Petty Officer
Joined
Sep 3, 2007
Messages
408
Re: Pumping fuel a gas pump

The fix, if needed is to check all your fuel lines. I doubt a 2001 would have a probelem with the ethanol because USCG type A and B hose has been formulate to resist ethanol since the 80's. But They are 9 years old and hoses should be replace periodically anyway.

As for the other problem, it is a common problem. Boats are designed to have the fuel tank vent at the high end of the tank, when the boat is sitting in the water. Sitting on a trailer it may not be at the same attitude and the vent may be at the lower end of the tank. If that is the case then you simply won't be able to fill the tank completely full.

So you need to locate the tank, locate where the vent line enters the tank and what its attitude is while sitting on the trailer. You may have to raise the trailer tongue while fueling to completely fill the tank, but if you do, when you lower the tongue the tank will burp through the vent.

Also some tanks have a 5 % Ullage, that is 5% of the tank capacity is above the level of the vent in the tank and is there strictly for expansion of fuel due to heat. You simply can't fill the tank completely if it has a 5% ullage.
 

SALARGO

Cadet
Joined
Aug 8, 2010
Messages
7
Re: Pumping fuel a gas pump

Hey Friends,

I take a look at the gas tank, after about an hour, I open the tank to check the level of my gas thru the sending unit it show the tank is full or almost full, that explain why I kept getting full at the pump. But, I found out that either my sending unit or may gas gauge is not working properly, it kept showing empty, afraid to run out of gas I always pump more to fill the tank. I really have bigger problem, How do I attack this?
 

Cruzomatic

Petty Officer 3rd Class
Joined
Aug 30, 2005
Messages
78
Re: Pumping fuel a gas pump

It's burping. Try filling the boat slowly it'll help it a lot.
 

Mischief Managed

Lieutenant Commander
Joined
Dec 6, 2005
Messages
1,928
Re: Pumping fuel a gas pump

Hey Friends,

I take a look at the gas tank, after about an hour, I open the tank to check the level of my gas thru the sending unit it show the tank is full or almost full, that explain why I kept getting full at the pump. But, I found out that either my sending unit or may gas gauge is not working properly, it kept showing empty, afraid to run out of gas I always pump more to fill the tank. I really have bigger problem, How do I attack this?


Replace your gas gauge (they are typically very inaccurate on boats) with a fuel flow meter that can be programmed with your gas tank size and displays fuel remaining. You'll know exactly how much gas you have left and can use that data to prevent burping during fuel filling.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
Re: Pumping fuel a gas pump

If your problem is filling the tank at a gas station on the trailer, try turning the pump nozzle "upside down", as though you were in the boat. Or, just go in the boat and hold it that way.
 

Peter Eikenberry

Chief Petty Officer
Joined
Sep 3, 2007
Messages
408
Re: Pumping fuel a gas pump

Either the guage is no good, or the sender is no good. Or you may simply have a bad ground or broken wire from the sender to the gauge. Check the wiring to make sure every thing is working. If you want to replace the sender there are much better ones on the market than the old arm and float. The newer ones use capacitance or inductance and are a lot more accurate.

Most are made by Wema http://www.wemausa.com/

There are even more expensive ones that are attached to the outside of the tank and have no moving parts.
 

SALARGO

Cadet
Joined
Aug 8, 2010
Messages
7
Re: Pumping fuel a gas pump

Friend,

I just order the sending from online site, is the fuel gauge on the same website universal that would fit my Key Largo slot or do I need to order form Key Largo manufacturer? TTY;:D
 
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