[ConfusedEnthusiast]

During storage, the vent must be kept closed to prevent evaporation and loss of your fuel as well as to prevent dangerous fumes from escaping, which could cause an explosion. This is especially true if your tank is stored in a locker or holding box. Gasoline vapors are heavier than air and can collect in a closed locker. When the right mixture of gas and air are present, any source of ignition can cause an explosion. With the right fuel air mixture, 1 gallon of gasoline has the explosion power of 20 sticks of dynamite. Although it’s difficult to get the right fuel, air mixture, it’s not impossible, so always err on the side of safety. [links]

[suntsu]

The vent on your gas tank is necessary to prevent a vacuum block which would prevent fuel from being pumped from the tank to your motor. It needs to be open when operating your motor. [links]

[Aaron]

I have a gas tank with a manual vent. Should the vent always remain open? If the answer is yes, how does one keep rain and other moisture from getting into the tank. I have kept it closed and the tank will balloon in the heat and implode when it is cool. I try to keep the tank full to prevent this however, there are times when the tank is not filled to capacity. As you probably are aware, this is a plastic tank.

[aaaa]

Plastic fuel tanks are designed and built to allow for expansion and contraction. That’s why fuel should only be carried, transported and stored in containers certified for that purpose. Even gasoline and diesel have different containers. here

[concetxos01]

For your convenience, I’ve highlighted the hyperlinks. Click on the hyperlink to get more information about the selected product. more

[Artefact2]

When you open the vent on an expanded tank, fuel vapors will escape. If the tank is sucked in, opening the vent will allow air into the tank to equalize the pressure. For safety reasons, opening the vent should be done off the boat on a level surface with good air circulation in the area and no ignition source present, even cell phones. Some boats will have explosion proof exhaust fans to vent the area prior to starting the engines and others will have will have proper ventilation built into the locker design. If in doubt, take the tank off the boat to open the vent and make sure that there are no fuel fumes on the boat prior to starting the motor. more

[Svick]

In summary - regardless of your engine make/model we always recommend reading your owners manual to make sure you're maintaining it as recommended by the manufacturer. Different brands, models & size engines require different treatment so that is the most reliable source of advice.

[privacyshark]

But if you leave old fuel in your carburettor for long periods (over three months), it can block your carburettor jets & galleries with tarnish build ups - meaning the engine won't run properly on restart. [links]

[trangcotich]

If it's an EFI four stroke it's not necessary to run them out of fuel as this motor doesn't have carburettors, so there's no risk of blocking the carburettor jets.

[mike_la_jolla]

The really short answer is that it depends on what sort of motor it is - so always refer to your owners manual from the manufacturer.

[Set WilliamA]

If you don't do this and you've had the fuel evaporate, you'll have more oil build up in the fuel mix than ideal - causing smoke & potentially hard starting when you go to start it next time. more

[Hansietorse3]

If it's a direct injected, EFI two stroke it's not recommended to run these out of fuel as some of the oil injection components run separate to the fuel system. If you run them out of fuel the oil will still keep injecting into the engine causing it to have extra oil on start up next time, and potentially cause hard starting. more

[Axcella]

Open the vent after you connect the fuel hose and tank to your motor. If you do not open the vent, your motor will experience a vacuum lock.

[pharaon]

Open the manual vent valve, if the tank does not have an automatic vent or a one-way air check valve installed, before you remove the cap to fill the tank. Close the manual vent after you have finished filling the tank. [links]

[psokol]

Put your ear close to the tank before you fill it. Listen as you loosen the gas cap to check whether air rushes into the tank. This indicates a problem with the vent.

[MarianelaHuf8544]

All outboard motors have vented gas tanks. As the fuel pump sucks fuel out of the tank, the fuel's departure creates a small vacuum inside the tank. If there was no way to fill that vacuum, it might overcome the pressure of the fuel pump and your motor would starve for want of gas. Some outboard gas tanks have a vent that opens as pressure inside the fuel tank drops, some have a simple check valve, and others have a manual vent you open yourself.

[ritobanb]

Remove the filler cap from the fuel tank if your motor begins to "gasp" while you are making way in your boat. If the motor runs when you remove the filler cap, but seems starved for fuel while the cap is in place, replace the tank vent system. more

[TranSlate]

more

[Aleks]

How do I know if my outboard fuel pump is bad?

[europazuz]

A primer bulb is important because it is helps to fill the carburetor with the correct amount of fuel. It does this by pulling fuel through the fuel line. You may need to fix or replace your primer bulb if: It is not creating proper suction. more

[jstn]

Keeping this in consideration, do you need a primer bulb?

[fresno]

RE: Fuel primer bulb The float has floated in the full bowl and the needle valve attached to the float has seated and cut off fuel flow to the carb. No fuel can flow, the bulb fills with gas, hard bulb. here

[Stone Man]

Similarly, what are the symptoms of having air in the fuel line? Air bubbles in a fuel line can lead to stalling, hiccuping or refusal to start. Keep your fuel lines free of air to help keep your car running smoothly. here

[sixtoxxy88]

From smooth sailing to a bumpy ride Sputtering or misfiring is another sign that the fuel pump may be on its way out. When the pump is not providing fuel consistently you will experience sputtering and may even find that the engine dies while the machine is still in motion. It's similar to running out of a tank of gas. more