How do I not overfill my tank?

[zimm]

Everytime I fill my boat, I get a big bubble of fuel blurp up and run out of the fuel fill. Usually right as the pump kicks off- blurrrrrp! Fuel everywhere. I even tried slowing the pump to the lowest setting as the tank was getting full.

 

[Doc Stressor]

I estimate the amount of fuel I'll be taking on and start listening when it should be close to full. As soon as I hear the fuel start to gurgle in the filler hose I stop fueling.

 

[zimm]

Hmmm.... I guess I'll have to be more careful. I guess they all do it since they got rid of the old school overflow vents on the side of the boat?

 

[DennisG01]

Listen for the "gurgling" sound. When you hear that, stop. You have to be there - you can't use the "auto" mode like you do in a car. There is a device that can be installed that's supposed to allow it to "auto off" -- I've read reviews and even had one in my hand, but never used it personally.

I have a "whistler" installed (by PO) in my boat. Works GREAT!!!! I should put one of these in all my boats.

 

[wspitler]

Make sure your vent is not clogged. Older boats have a very fine screen that is easy for insects to clog while newer boats have the vent integral in the fuel cap which prevents the clogging issue.

 

[enfish]

Wrap a towel around the fill nozzle. I know this doesn't solve the issue, but it keeps the mess to a minimum. Every fuel dock on the water I've been to does this as standard procedure.

 

[seasick]

Everytime I fill my boat, I get a big bubble of fuel blurp up and run out of the fuel fill. Usually right as the pump kicks off- blurrrrrp! Fuel everywhere. I even tried slowing the pump to the lowest setting as the tank was getting full.

If the fuel vents out when you start to fill then your vent line is probably plumbed incorrectly. There should be a high loop in the vent that will allow sloshing fuel to run back into the tank, If there is a low spot or loop, fuel will accumulate and when pumping starts, that blob of fuel spits out the vent.
Depending on you vent configuration, there are overflow containment gizmos that can be placed under the vent to catch overflow when refueling..

 

[zimm]

Everytime I fill my boat, I get a big bubble of fuel blurp up and run out of the fuel fill. Usually right as the pump kicks off- blurrrrrp! Fuel everywhere. I even tried slowing the pump to the lowest setting as the tank was getting full.

If the fuel vents out when you start to fill then your vent line is probably plumbed incorrectly. There should be a high loop in the vent that will allow sloshing fuel to run back into the tank, If there is a low spot or loop, fuel will accumulate and when pumping starts, that blob of fuel spits out the vent.
Depending on you vent configuration, there are overflow containment gizmos that can be placed under the vent to catch overflow when refueling..

It only overflows when it's full. I should have clarified.

 

[seasick]

Everytime I fill my boat, I get a big bubble of fuel blurp up and run out of the fuel fill. Usually right as the pump kicks off- blurrrrrp! Fuel everywhere. I even tried slowing the pump to the lowest setting as the tank was getting full.

If the fuel vents out when you start to fill then your vent line is probably plumbed incorrectly. There should be a high loop in the vent that will allow sloshing fuel to run back into the tank, If there is a low spot or loop, fuel will accumulate and when pumping starts, that blob of fuel spits out the vent.
Depending on you vent configuration, there are overflow containment gizmos that can be placed under the vent to catch overflow when refueling..

It only overflows when it's full. I should have clarified.

In a way that's a good thing!
You have two choices: Estimate how much the tank will hold and stop a few gallons before that number ( often tough to do)
See if you can find one of those overflow gadgets that catches the excess fuel. Here is a link to one such product
http://www.tgmmarine.com/nospills/pages/products.html

 

[GulfSea]

More than likely the tank is/was installed a little off level and traps an air bubble that slips to the fill area just as the tank tops off. If it were mine, I would observe where the fill hose enters the tank and manipulate the boat to make sure that side is higher on the next fill up to see if it made a difference. If not, the next suspect would be vent tube routing, security and/or blockage.

 

[rcrudder]

I use a towel, estimate how much fuel I will need and listen for the gurgle in the spout.