Full Answer
What does it mean when your outboard fuel line is blocked?
A blocked outboard fuel line prevents fuel from getting to the motor. It generally starts with a partial blockage, where playing around with the fuel hose and pumping the primer bulb will get the motor to start or keep it running.
How does fuel get into a boat without a fuel switch?
Or, if your boat doesn’t have a selector switch, it should lead to a fuel water separator. Once the fuel passes through the water separator, it then comes out the other side into a primer bulb or straight to the engine.
What causes a boat engine to run out of fuel?
And still, experience an engine running out of fuel. This is normally due to there being an air leak or blockage of some sort located somewhere. Between the pickup tube that is in the fuel tank, to the engine lift pump. What Causes a Boat Motor to Lose Power?
How does a boat fuel tank pickup work?
You have the fuel tank pickup in the tank. This leads to a hose barb that feeds the fuel to one of two places. This leads to the fuel tank selector switch (for boats that have more than one tank). Or, if your boat doesn’t have a selector switch, it should lead to a fuel water separator.
How do I get air out of my outboard fuel line?
Insert the clear hose into the fuel line, prime up the engine, and start it up! Let it run for a little while and carefully watch the fuel passing through the clear hose. If you see a ton of air bubbles coming from the boat fuel tank side of the hose, then we are hot on the trail to solving this issue!
What causes air in fuel line?
Your fuel supply system is between your fuel tank and the transfer pump. A leak in this area can lead to air getting sucked in by the fuel system. Lastly, a failed injector combustion seal is another common cause of why air gets into your fuel system.
How do I find an air leak in my boat fuel line?
Plumb in a clear piece of hose into the fuel system, as close as you can to the VST tank. Somewhere after the primary fuel filter. Monitor the hose for the presence of bubbles while the motor is being run at high power. Or, have someone pump the primer ball continuously while the motor is being run at high power.
Is it normal to have air bubbles in fuel line?
Bubbles are not necessarily air, they can be vaporized fuel. This can happen if say the fuel line comes close to the muffler and is warmed up then some of it flash's to vapor when it drops pressure across the remote needle. It can even happen if it does not come close to the muffler on a hot day.
What happens if a fuel tank is not vented?
Without a vent, an end user will notice a swelling in even the smallest of tanks. Many smaller vent caps are simplistic and just have an internal spring. The spring acts as a relief valve and exhausts the pressure in the tank. Furthermore, the vent allows air to enter the tank, as well – it's a bidirectional valve.
What are signs of vapor lock?
What are the Symptoms of Vapor Lock?Stalling and Hard Starting. A gasoline engine needs three primary ingredients to run: a precise air-fuel mixture, good compression, and proper spark. ... Misfiring and Rough Running. ... Poor Acceleration and Hesitation.
How do I find a vacuum leak on an outboard motor?
3:0421:52Finding a vacuum leak - YouTubeYouTubeStart of suggested clipEnd of suggested clipA tallish unlit. So you're not lighting it like you would normally you're just having the gasMoreA tallish unlit. So you're not lighting it like you would normally you're just having the gas flowing. And then just start directing that flow of gas.
How do you prime a outboard fuel line?
First, connect the fuel line to the engine, if not already attached, then pump (squeeze) the bulb repeatedly until it's firm. It usually only takes a few pumps. When the bulb is firm, the line is charged and you can start the engine.
Does a 4 stroke outboard need a primer bulb?
Most of the newer fuel injected engines don't really need them, but you will need it to refill an emptied fuel filter in the hull. My 2014 Mercury 150 hp 4 stroke does not have a primer bulb. And it starts every time on the first try.
How do you bleed air from a fuel injection system?
1:034:38Fuel System Bleeding - YouTubeYouTubeStart of suggested clipEnd of suggested clipYou can loosen that and then if it's a mechanical pump. The mechanical pumps will have a lever onMoreYou can loosen that and then if it's a mechanical pump. The mechanical pumps will have a lever on the bottom of the pump like this one does and you pump that lever and fuel.
How do you fix air in your gas tank?
2:223:22Fixing A Car Where The Gas Pump Keeps Shutting Off - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd plug. It into the canister where the fuel tank line went then apply air pressure to it. And ifMoreAnd plug. It into the canister where the fuel tank line went then apply air pressure to it. And if you don't feel air coming out of the other ports. It's clogged up and needs replacing.
What causes air lock in gas tank?
Air locks are caused by air leaking into the fuel delivery line or entering from the tank. Air locks are eliminated by turning the engine over for a time using the starter motor, or by bleeding the fuel system. Modern diesel injection systems have self-bleeding electric pumps which eliminate the air lock problem.
What happens if you block an outboard motor?
It generally starts with a partial blockage, where playing around with the fuel hose and pumping the primer bulb will get the motor to start or keep it running. But blockages don’t cure themselves. In a few days, squeezing the primer bulb does less and less, possibly getting to the point where there is no resistance in the bulb and it does not expand when released.
Why do new hoses have an impermeable liner?
New hoses have an impermeable liner to keep ethanol from degrading the other hose material. That liner can delaminate from the outer hose and cause blockages. The hoses with the grey outside coating (UV protection) seem to have more problems than others. Attwood brand hoses seem to have more problems than some others.
Why is my boat running out of fuel?
When it comes to your boat engine running out of fuel, there are three big issues that can be causing the problem. Either the engine’s lift pump has failed, the boat is out of fuel. Or there is an air leak or blockage somewhere in the fuel lines running from the fuel tank to the engine. It’s important to remember that there are many different types ...
What happens when a fuel line is blocked?
If you have a strong lift pump and primer bulb, you’ll notice that the lift pump will suck the primer bulb flat. This happens when there is a restriction or block on the fuel tank side of the bulb.
How do mechanical fuel pumps work?
Mechanical fuel pumps are usually operated by either a diaphragm or crankcase pressure or an arm and a lobe on the camshaft. For more information on lift pumps, FSM’s, or VST’s and this issue.
Why does my engine run out of fuel?
And still, experience an engine running out of fuel. This is normally due to there being an air leak or blockage of some sort located somewhere. Between the pickup tube that is in the fuel tank, to the engine lift pump.
What happens if you don't have a fuel water separator on a boat?
Or, if your boat doesn’t have a selector switch, it should lead to a fuel water separator. Once the fuel passes through the water separator , it then comes out the other side into a primer bulb or straight to the engine.
Where is the blockage on a boat fuel tank?
The second most common location for blockages is going to be on the bottom of the fuel tank pick up. More often than not, fuel tank pickups will have screens on them. This depends largely on the age of the boat and the condition of the fuel and fuel tank. This pick-up screen can get clogged and creates a blockage.
Where are the shut off valves on boats?
Nowadays, most manufacturers use shut-off valves on the water separators and have the lines above the top of the tank.